Finningley,
Glad I was able to be of help. Perhaps I can offer a little more help.
The basic point is that the F-35B is required to be a STOVL aircraft. This means that it has to pay a range/payload penalty. This was known and understood from the outset, and the original JSF requirement document reflected this in a shorter range requirement and reduced weapons carriage requirements (amongst other things).
The UK is buying a STOVL aircraft because that's what the original UK requirement (NST 6464) was for - a Sea Harrier replacement to operate from RN ships. The UK got its Tier 1 level partnership partly due to its STOVL knowledge and expertise - the US JPO acknowledged that the STOVL variant was technically the most risky and they needed our help. NST6464 morphed into Future Carrier Based Aircraft (FCBA) and on formation of Joint Force Harrier, FCBA was renamed FJCA (Future Joint Combat Aircraft). None of this should obscure the fact that the UK said it wanted a STOVL aircraft and that it what it's getting. What has changed, and I think sometimes isn't clearly spelt out, is that the F-35B is now being required to be a Tornado replacement as well. I can fully understand that some RAF aircrew would see the need for a Tornado replacement as being more important that getting an aircraft to operate from aircraft carriers.
I'll repeat what I have posted many times - to me it would make sense for the UK to formally investigate a revised F-35 buy, replacing 138 F-35Bs with (say) 85 Bs and 65 less expensive As. The two variants could use a largely common training and support system, reducing the additional costs of running the two variants. The As could then come under full operational control of Air Command, with the Bs under Sea Command. Bs could still 'flex' over to land based roles by Sea Command if requested by Air.
For all I know this has already been looked at. Just my thoughts.
Incidentally, the F-35B doesn't need 'more' fuel to drive the lift fan shaft. The main engine operates as per usual, and the shaft extracts around half the power down the shaft to drive the fan. Because the fan is using cold air, the overall lift is developed using less fuel than by other options. When the F-35B does a VL, the main nozzle is actually operating at about half full thrust. Hope this helps.
Best regards as ever to all those working out the future force details,
Engines