Wiring of light switch

[ETAF]

but I was trying to save a bit of cash by installing the lights and wiring the switch myself

If you put all the wires in and lights then as asked , draw a diagram of what you did
colours of wires , dont mean anything on there own, its you who would have used the colour of the wire to connect up things
so saying

With the lights I'm just placing the blues together in one hole and the browns together in the other hole, and earth to earth of course.

doesn't mean a lot

Blue can be used as a switched Live, so NOT a neutral ......

so a simple diagram showing the setup

ONE WAY TO WIRE
assuming that yiou =have 2 lights and you used 2 bits of T&E for each light
then you would have for each light , if wired as convention
Brown - switch live
Blue - neutral
Bare - Earth (needs a sleeve green/yellow

and then the 3rd T&E would be LIVE/ Neutral form a power source

so the LIVE from the power source - Brown - would goto COMM on the switch
The other 2 Browns - switched Live out to the lights , would go in L1 or L2 - matters not - just how the switch would work for on

BLUES all together in a wago - and NOT connected to the switch at all

BUT there are manyways you could have put the wires in

can you do the following as asked in previous post

ok, so how did you wire the lights up ....
do you have 3 T&E cables , what does each one do ????
Live/neutral IN
switched Live / Neutral to one light
switched Live / Neutral to second light

if its a new installtion can you draw a diagram of how its all setup ?