Confirming I've got this right...

[mapj1]

Actually, a great many TT supplies just have one 30mA RCD as incomer, and while this can be troublesome with nuisence operation, it is very often not so - many cheaper TT rewires just have one 30mA trip for the whole shabang and never a show a problem. The fact that even the NIC give such a set up a mere code 4 says something.
The chance of an NE fault occuring suddenly at midnight is virtually nil.
It usually concides with drilling holes or nailing something. As such taking down the whole house is a good warning. The problem of large installations is total LE leakage, not NE faults appearing suddenly. I'd suggest you don't really need to do very much to what you have.

Here is the list I have

Only one code per departure Is allowed
Code 1. Items that require urgent attention
1 Main bonding to incoming extraneous services (eg,water, steel etc) not evident
2 Means of earthing to the premises not evident
3 Incorrect polarity
4 Barriers, blanks or insulation missing from equipment, allowing access to live parts (IP2X not
achieved).
5 Class 1 items of electrical equipment installed on circuits without a circuit protective conductor
(CPC)
6 Extraneous-conductive-part being used as means of earthing, e.g. water or gas pipe
7 Circuit cables overloaded to such an extent that they may pose a fire risk (cables max operating
current exceeded)
8 Measured /calculated earth loop values that exceed max disconnection time allowed and there is not evidence of any supplementary method of protection
9 Touch voltage too high on a TT installation (refer to Regulation 413-02-20)
10 Insulation resistance values less than 0.5 MΩ on any circuit, 2 MΩ on a combined installation, or
0.25 MΩ on a SELV/PELV circuit
11 Fixed heating generating equipment focused on, or adjacent to, combustible material
13 Inadequate fault current protection of cables
14 Inadequate fault breaking capacity of protective device
15 Green/yellow insulated or a bare CPC in a twin & earth cable used as a live conductor.
16 Neutral to earth faults on a system
17 Wiring or equipment connection that could result in overheating
18 Socket outlets not provided with RCD protection on a TT installation
19 Socket outlet, without the defined method of protection (see Regulation 601-08), installed in a room containing a bath of shower
20 Touring caravan points supplied via a PME supply

Code 2 - Items that require improvement
1 Electrical connections not within a suitable enclosure for preventing ingress of moisture or solid
objects
2 CPC not provided on cirouit(s) supplying insulated or Class n equipment
3 Supplementary earth equipotential bonding in bath /shower room not evident, or has been omitted on some items may require it
4 Supplementary earth equipotential bonding not carried out between equipment in Zones A ,B & C of a swimming pool installation
5 Electrical connections not contained within a suitable enclosure having Class P fire characteristics
6 Damaged equipment, unless that damage allows access to live parts.
7 Cables installed outside of mechanical protection zones without additional protection
8 Socket outlets provided for use of 230 volt hand held equipment on a construction site.
9 Total leakage current on a circuit supplying IT equipment has not been allowed for, as required by Section 607
10 RCD protection not provided for socket outlets that may reasonably be expected to supply
portable equipment outdoors.
11 Insufficient detail on Distribution Board Schedules
12 Isolators not identified
13 Voltage Warning Notice not evident on equipment where the operating voltage exceeds 230 volts
14 RCD Test Notice not provided
15 Cable(s) has inadequate means of support
16 Cable entries to equipment/enclosure are not provided with mechanical damage protection
for cables
17 Excessive sheath removed from cable(s), resulting in exposure of insulated cores outside of
equipment/enclosure
18 Earth electrode connection inadequately protected against mechanical damage



Code3 - Items that require farther investigation to resolve
These are items where some of the installation or circuit integrity cannot be readily assessed during the inspection.

Code 4 - Items that do not comply to the current requirements and is not unsafe
1. Main bonding conductors not sized in accordance with the current edition of the IEE Wiring Regulations.
2. Supplementary earth equipotential bonding in a room containing a bath or shower, does not meet with all the requirements of Section 607 in the current edition of the IEE Wiring Regulations
3. CPC identified green and not green /yellow
4. Unsleeved CPC evident at equipment/accessory connection point
5. Periodic Inspection and Testing Notice not provided
6. Periodic Inspection and Testing Notice inadequately completed
7. "Safety Do Not Remove" labels not evident at earth connection points
8. One RCD used to protect all circuits within an installation
9. Discrimination not achieved between protective devices where necessary to meet requirements

PLEASE NOTE: THE FOREGOING IS ONLY INTENDED AS A GUIDE AND NOT AS A SUBSTITUTE FOR SOUND ENGINEERING JUDGEMENT

 

[pdcelec]

2. Supplementary earth equipotential bonding in a room containing a bath or shower, does not meet with all the requirements of Section 607 in the current edition of the IEE Wiring Regulations

Is this bit correct?. How many people have IT equipment in the bathroom?

 

[ban-all-sheds]

Not many, although as the increasingly witless domestic appliance designers are now putting IT equipment into fridges, bathrooms are bound to happen one day.

And don't tell me that there isn't someone, somewhere with a webcam in the shower

But I digress - 607 also refers to heating elements.