Buster, take a look at this link for latest prices. Top line: F-35B $122.8M a copy including engine/lift fan. So, at current exchange rate it's ~£100M a copy mark. I expect it to drop again in successive LRIPs, broadly in line with the cost curve in an earlier but fairly recent post.
LRIP-10 F-35 cost: Lockheed Martin says Trump helped get lowest prices - Business Insider
F-35 roles include: SEAD/DEAD, Strike (AI, Attack), OCA/DCA, CAS. In many cases swing-role (it is amazingly optimised for switching roles quickly) however you are right in saying it is primarily a self-escort bomber, however I'll add that its A-A is extremely potent. Where it lacks over F-22 (other than 2 engines and TV) is internal missile carriage. This has been debated here many, many times. F-22 ran at around $180M a copy. Now that's expensive.
There is no other aircraft built that has the fused sensor SA and stealth combination of F-35. For the money, it's a lucrative prospect for U.K., which is why time and again the Government has supported the operational analysis for buying the F-35B. It presents the best, most flexible variant which meets the carrier configuration. Look at the NAO audit on the B to C to B debacle to see what changing to Cat/Trap would have cost. Again, another mired discussion also presented on here many times.
I fear we'll never agree, but it's of no consequence as the facts will argue themselves.