Shabs wrote:

I have been further looking at my consumer unit installation (had
problems previously) and noticed my "cooker" feed has 6mm T+E cable
but no electric cooker. Furthermore i have no intention of ever
buying an electric cooker. Instead it is being used as a feed for the
boiler, washing machine, fridge, and microwave. It has now
effectively become a radial socket circuit.

Because the initial wire is 6mm for about 4-5 metres which has a
socket attached, then a spur to a further double socket, am i correct
in thinking a 40amp MCB is too high for this purpose? Would a 32amp
or 16amp be more appropriate or is this not the case due to the cable
being 6mm and requiring a 40a mcb regardless of use.

Thanks in advance.

The idea is the MCB goes before the (putatively shorted cable) catches fire.

i.e. Make sure the MCB is the Ann Robisnon of your circuit.