I'm looking at replacing a somewhat old consumer unit. I'll freely
admit that my electrical skills are not up to it, and I probably don't
have all the necessary test kit, both of which are a shame.

Anyway, a local firm has scented an opportunity (all the places on the
same development have the same, old, consumer unit) and have sent
round a fuzzy before and after picture of what replacing with a new
RCBO based unit would look like, and estimated a standard price, with
an addition if you need more 'ways'.

Anyway, it looks, from the picture, as though they'd remove isolating
switches and seem to have a design that has:

a) an RCBO per way; and
b) an RCBO acting as a 'main fuse', sized to be 'equivalent to' the
current main fuse.

Hence the question in my title. Is an RCBO a suitable isolator? And is
the rest of the design sensible? I can't tell from the text, or the
fuzzy picture, but I would assume that the RCBOs per way would be fast
acting, and the 'main fuse' replacement would be slow acting -
otherwise a nuisance trip could take out the whole board, which is
what I though we were trying to move away from.

If the supply is rated at 60A, is that what they would propose for the
'main fuse' equivalent? My understanding is that RCBOs (and MCBs) are
less 'forgiving' of overcurrents than fuses, so I'd actually lose some
peak capacity (not that I use it, but some might).

Of course, I can put the same questions to the firm that put the flyer
through the letterboxes, but I'd prefer some independent opinion
first, if that's possible. Thanks!

Sid