On Thu, 15 Oct 2020 15:34:56 +0100, PeterC
wrote:

Just placed an order for:
ST100HT Silent Tornado Hi-Power
Bathroom Fan with Humidistat & Timer
(Love the way it claims high power (not wanted) then boasts about
"low energy" of 7.5W - not bad for an electrical business!).
After placing the order the confirmation page had:
"Faulty Items
All warranties for all electrical items are invalidated if not
installed by a fully qualified professional electrician. We
cannot accept the return of any item deemed faulty unless
it has been installed by a fully qualified professional
electrician registered to one the UK's five trade bodies:
NICEIC, NAPIT, ECA, ELECSA, JIB.

In order to verify the proper installation of the item and
the integrity of the electrical system into which it was
installed, including circuit protection devices and fuse
board, we may need to speak to the installing electrician.
For this reason we require that the customer provides full
contact details of the installing electrician at the point
of return, including the trade body to which they are
registered and their registration number.

We cannot process any refund or replacement for a faulty
item without this information."

I wouldn't have bought had I known (i.e. thought to read Ts&Cs beforehand)
but I do consider it to be unreasonable. I wonder if it breaches Consumer
laws. I'm more than capable of fitting a fan; the existing one is on RCD,
MCB (lighting circuit) and has a SFCU in the supply (it's not operated by
the light switch).
The only reason for getting a new one is that the present one is sometimes
sounding a bit 'strange', nothing serious but I decided to fit a new one and
keep the old one as a spare. Better than waiting for magic smoke/terminal
sulking or whatever.

https://www.extractorfanworld.co.uk/...item-101-c.asp
doesn't mention this and as you say it is buried in their T'c & C's.
If you simply want to cancel and are within 14 days or receipt of the
goods the " Consumer Contracts (Information, Cancellation and
Additional Charges) Regulations 2013 S32" is the bit you need.

If it's any help extractorfanworld appears to be a trading name of
part of Gil-Lec Ltd, an electrical wholesaler with shops in Hemel
Hempstead and Chesham. I've used them a few times over the years (not
for fans) and always found them to be more knowledgeable and helpful
than most wholesalers.