" Currently we are looking at Vaillant.co.uk boilers:

http://tinyurl.com/o1er

Just installing a Vaillant now - seems well made with very high quality
fittings and ready-made tails. Very helpful tech advice line. About 35%
more
expensive than the equivalent Potterton. I am not clear how good the
Potterton is, so cannot compare.

Geoff

Potterton have made one or two shockers (Suprima springs to mind). Vaillant
do have a good name. I've been very satisfied with some Glowworm & Ravenheat
combis that I've used. BTW the usual experience on this group with plumbers
seems to be a reticence to recommend/install condensing combis because of a
lack of knowledge - it would appear that you have found one of the few who
has taken the time/trouble to keep abreast with current technology. The rest
will all have to follow suit shortly as new energy efficiency requirements
will effectively compel the use of condensing technology.

Neil