1. Nope, RS will sell to anyone and also offer free shipping, I use them regularly.
2. Buy a crimp tool and stripper, seriously. You can get a good enough ratchet crimper for £13 and the stripper will cost you ~£5, most of the ones for CCTV will do BNCs for RG58, Maplin sell them. The crimp plugs are trivial to fit with the stripper and ratchet crimp and cost 60p each, if you buy a bag of 100 they're as low as 19p each (and yes, that is a bag of 50R plugs for RG58, not 75R RG59 CCTV ones).
The time and effort saved as well as the price of the plugs will cover the cost of the tools really quickly.