Otherwise consider �50 to "service" the LP12. ?�200 for an RB300 (What else would you bolt on it Steve? Is there a cheep Linn arm these days?)
Linn and cheap don't go together! Fitting a RB251 might be a solution, but the LP12 would need a different arm board (another �40), it all depends on what the LP12 had on it before.
?�200 for an RB300, ?�150 for a Goldring 1042 cartridge. "Bargain" 562 (�150) and a ProJect PhonoBox II (�75) from ebay. That's �625 and I'm trying fairly hard to stick to a budget
The price quickly adds up with vinyl. I gave up on the Linn upgrade path a while back.
If the OP is determined to use the LP12, he needs to find out what arm was on it and get one to suit.
I would sell the LP12, if it is in good condition and has a valhalla power supply, it could easily fetch �400 on eBay. Strip it to it's component parts and you'd get even more.
Steve.