Cligga is good for tin and also Wherry, the hard part is going to be reducing it in size sufficiently to smelt lots of tin out, if you dont have access to a labs crusher one option is to blank one end of a short steel pipe off and use a close fitting bit of round bar as a hammer to break stuff up.
Its a shame you werent asking a year ago, there is a new Devon tin producer that is currently on stop.
Alloying to make bronze is tricky too, the tin likes to vaporize at the temperatures copper melts, bear in mind you could lose what you have worked hard to get. I'd suggest getting some copper & tin concentrates online and have a go with those first.
As a side note, you want to be careful with South West copper ores, easy to get a bit of arsenic fume off them...