I eventually found The Wildlife (Northern Ireland) Order 1985 online - they dont make these things easy to find and as for translating them !!!
As for the rest of the UK it seems to prohibit everything except a firearm. It mentions a bow or a spear by name and seems to exclude everything else as well
(1) Subject to the provisions of this Part, if any person
(a) sets in position any self-locking snare which is of such a nature and so placed as to be calculated to cause bodily injury to any wild animal coming into contact therewith;
(b) uses for the purpose of killing or taking any wild animal any self-locking snare, whether or not of such a nature or so placed as aforesaid, any missile which is not discharged from a firearm, including in particular any arrow or spear, or any explosive other than ammunition for a firearm; or
(c) uses as a decoy, for the purpose of killing or taking any wild animal, any sound recording or any live mammal or bird whatever,
he shall be guilty of an offence.
(2) Subject to the provisions of this Part and to those of Article 20, if any person
(a) sets in position any of the following articles, being an article which is of such a nature and so placed as to be calculated to cause bodily injury to any wild animal included in Schedule 6 which comes into contact therewith, that is to say, any springe, trap, gin, snare, hook and line, any electrical device for killing or stunning or any poisonous, poisoned or stupefying substance or muscle-relaxing agent;
(b) uses for the purpose of killing or taking any such wild animal any such article as aforesaid, whether or not of such a nature and so placed as aforesaid, or any net;
(c) uses for the purpose of killing or taking any such wild animal
(i) any automatic or semi-automatic weapon;
(ii) any metal bar, axe, hatchet, cudgel, club, hammer or similar instrument;
(iii) any device for illuminating a target or any sighting device for night shooting;
(iv) any form of artificial light or any mirror or other dazzling device; or
(v) any gas or smoke not falling within sub-paragraphs (a) and (b); or
(d) uses any mechanically propelled vehicle in immediate pursuit of any such wild animal for the purpose of driving, killing or taking that animal,
he shall be guilty of an offence.
Oops - just noticed that the act is subject to copyright restrictions -
So its an offence to contravene the act but its also an offence to copy any part of the act in order to tell someone else about whats in the act.
I always did like Monty Python