On 2 Nov 2020 23:49:35 GMT, Roger Hayter wrote:

In terms of getting the old tap off, I can see that is very likely
to
be a problem. Tricks I'm aware of: penetrating oil, light tap
with a
hammer, heat, Please let me know if there's anything else.

Depening on what was used to seal the tap to basin penetrating oil
might not have much effect on 30+ year old plumbers mait. It'll be
set hard and solid. Remember the basin in porcelain, it can crack, be
very gentle tapping the tap. The hole in the basin won't be perfectly
round, if the plumbers mait is in the void between tap stem and sides
of hole you could be trying to force round something that wants a
bigger hole to rotate.

Heat, I wouldn't. OK the basin has been fired but that would have
heated and cooled the whole thing fairly evenly, not sure how the
glaze would take to being spot heated.

One quick question on that: am I likely to be better off with a
fixed
or adjustable basin wrench?

I think this kind is more likely to enable access:

https://www.screwfix.com/p/basin-wrench-1-/14631

I find with adjustable almost anything is that they have a habit of
adjusting themselves looser as your fiddling about gettting them onto
what ever. Or loosen if you don't keep the pressure on them that is
holding the setting.

But it is well worth getting one of this kind:

https://www.screwfix.com/p/basin-wrench/13294

Having said the above the tolerance on these fixed type basin
wrenches leaves a little to be desired. Generally they are a loose
fit to the back nuts but at least once fitted and held up don't "self
adjust" and when rotated will grip the back nut.You can also clamp
mole grips or similar to the shaft to provide a good hand grip or
something gently tap.

--
Cheers
Dave.