For future reference, lots of
BBS wisdom on this issue saved here.
Edit: Andrew as for your pleas for a gunsmith who you could pay to do the work, there are various skilled 'smiths around the country, although none is likely to come forward publicly on this forum for fear of being seen to tout for business, which is forbidden (though I suppose they might PM you).
Jon's offer of help is generous but he's right when he suggests doing it yourself. The old BSAs are extremely simple to work on and you will enjoy it, as well as knowing exactly what's happened inside your rifle. Maybe the best thing would be to advertise for an enthusiast who lives near you.
Where is Pulborough - I've never heard of it, sorry?