In my experience (as a chippy) for painted finish woodwork the decos always seem to go gloss paint the woodwork first, then emulsion the walls afterwards.
For lacquer work (clear finishes) we often install the woodwork, which is pre-lacquered, after the walls have been painted. If necessary to reduce the gap between the plasterwork and the top of the skirtings you almost invariably have to hack away the crap left by the plasterer (below top of the skirting line) using a hammer and an old chisel (or in my case an electrician's bolster chisel). Plasterers rarely leave the bottoms of walls plunb IMHO. After that you may still need to resort to power planing out areas at the back of the skirtings in order to achieve a tight fit to the wall. On tiles floors where the tiles have gone first it may also be necessary to scribe the bottom of the skirtings to the tiles. You may also need to deal with humps and hollows and hollows in the floor by scribing the underside of the skirtings. To do a clear lacquer finish job properly it is a step up in skill level from nailing painted MDF or softwood in place, especially as hardwoods should also be drilled, countersunk, screwed and pelleted in place and there is also a bit more skill to peletting properly, especially as the decos can do nothing to correct errors in grain orientation or pattern that you may make (although the good guys are adept at matching colour mismatches, I've found). But what you always try to avoid with clear lacquer work is to fit it with a big gap to the wall then put a 10mm width run of caulk in, as you just can't hide that (although coloured caulk can help) - unlike nice white painted woodwork where you can simply paint over the caulk
