ARW wrote:
Before I fit the CU to the wall and remove any knockouts I will have
a play on the bench with it and see how much of a mare the various options
are and will report back before I do anything permanent on the CU.

Thanks to all for all the advice up to now

Forget using the knockouts. Jigsaw or angle grind them into one big
slot[1], superglue on grommet strip and your job will be much easier.

.... and then how do you manage the flame retardant seals needed by the
latest regulations?

--
Chris Green
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