I need to replace our non mains pressure HWC, it's about 30 years old and has started leaking.  It's built in and going to be hard to get out, and the space available may mean it's tricky to put the "ideal" size mains pressure cylinder in the space available.

Is there a reason why I shouldn't put a mains pressure cylinder in the basement below?  There's tons of headroom, all the plumbing is under the floor and should be easy to connect to, cabling is already there, and it would free up space and give us a large storage cupboard in the laundry. I guess there'd be some loss of pressure, but the mains pressure seems to be quite high, dropping the cylinder ~ <3m should be less than 0.5 bar loss.   Asking before I call a plumber who'll no doubt have the right answer, so I can think about stuff I'll need to do to make the job as small a mission as possible.

Apart from one shower mixer (venturi type), all the tapware can be converted from unequal to equal pressure easily where needed, and all the pipework is copper in good condition / good quality.  I've already got a booster pump in line to a shower which works far better than I expected, though it's quite a big pump (300w motor IIRC) - not the little ones sold on TM etc, and the noise it makes is okay as it's in the basement.