"Ric" wrote:
Grippers: I intend to nail these down (spikes pointing towards skirting
of course!) about 1/4 to 1/2 inch away from the skirting. Is this about
the right distance and how important is the distance? Anything to watch
out for when going round architrave/chimney breast?

I go for 8mm - about 1/3 of an inch. If it's wrong the fitter
will probably take them up and put them back again (and
charge you). If they're too far from the wall, the carpet won't
fold snugly down into the gap and you might even be able to
see floorboard at the edge. 1/2 inch is way too much IMHO.

Underlay: No problems with the cutting of this - although not entirely
sure how close it should get to the grippers - should it touch them or is
there are a gap?

Touching is fine, but not so it bunches up against the gripper.

I also thought that it was just a case of putting it in place but the
packaging says that it should be fixed with staples or adhesive- what
methods of fixing would people recommend?

I have always stapled it with a staple gun, until the fitter who
did our lounge/diner left me a can of the spray adhesive they
use. Stuff is magic! Used it to put underlay in our porch and
it stuck the underlay to the (fairly rough) concrete like glue
(which isn't altogether surprising, but you know what I mean).
Also, staples are a pig to take out when you replace the carpet.

Once the underlay is fitted, what tape should be used to seal
the joins?

I've never bothered. Very little lateral force on a carpet, so as
long as you cut the underlay accurately you shouldn't need it.

HTH,
Al