Yes, I realise it was a bit of tongue in cheek, if you look at my last post, I have discovered there is an earth bond and the revised quote of £418 involves no cable runs just fit a new RCD & housing for two circuits, Hob & cooker which are currently connected to a Square D Quickline CB which only has a 100amp main switch, all ring mains are on a separate CU which has a RCCB.
I am having a new consumer unit installed and got two quotes, one for £400 and one for £150 which does seem very cheap. I am going with the lower quote partly as it's the cheapest, but also he has done work for friends (an almost complete rewire) which they were very impressed with.
There is no earth bonding required as this was done when a new electric shower was installed and this has its own separate modern consumer unit, so this may explain why the quote is low.