teamhillside wrote:
We have an old roll top cast iron bath which has taps which come
through the sides. I believe they are called "globe taps" (http://
http://www.salvo.co.uk/images/userim...67/26988_1.jpg is a picture I
found).

I'm no plumber (!), but I reckon a dripping tap ought to be within my
capabilities. I expect the issue to be a failed washer, so I will
need to turn off the water supply, remove the top, replace the washer
etc.

Not familiar with that particular tap, but the above sounds about right.

Things I need advice on:-
- its the hot water tap, and we have a combi boiler. Do I turn off a)
the boiler b) the cold water feed c) both the boiler and the cold
water feed? Which combination is best for the boiler, best for me!!

If you turn off the mains the hot & cold should both stop. The boiler won't
fire, but you can turn it off if you want.

- what size washer is likely to be required in one of these taps? I
would like to have the most likely culprit available to hand, so if
its going to be something non-standard it would be good to know in
advance! I believe most bath taps use 3/4" washers?

So do I :-)

- any likely pitfalls I'm going to fall into with this type of tap? I
would much rather not have them at all, but SWMBO likes them. I know
that they are not an approved type of tap these days (something to do
with water from the bath being able to get into the cold water
supply?) but I presume someone has some experience of them?

Depending on age replacing the washer may not solve the problem. The tap
seat may be scored & need reseating. Thats rare IME.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk