Are you on the slopes or flat land?? There are already a few people growing rubber in your district.
Btw, where is your land in UK ?
I have to tell you that rubbers tappers are not easy to find these days. They are a dying breed. So please check availability of tappers in your area. Of course that would be 5-7 years from now 
Below is a list of varieties that are approved by RB.
Category I RRII 105, PB 260, RRII 414 and RRII 430, RRII 417 and RRII 422
Category II RRIM 600, GT 1, RRII 5, PB 28/59, PB 217, RRII 255, RRII 203, PB 280, PB 312 and PB 314
Category III RRII 50, RRII 51, RRII 52, RRII 118, RRII 176, RRII 208, RRII 300, RRII 429, PR 107, PR 255, PR 261, PB 86, PB 5/51, PB 235, PB 311, PB 330, RRIM 605, RRIM 701, RRIM 703, RRIM 712, RRIC 100, RRIC 102, RRIC 130, KRS 163, IRCA 111, IRCA 130, SCATC 88-13, SCATC 93-114, Haiken 1, BPM 24 and Polyclonal seeds
For the first 3-4 years you can grow Bananas, Pineapples, Turmeric, Ginger etc as inter crops with rubber. Ive seen people growing timber along the border of rubber plantations.