How to repair those stuck Defender flaps. 

Those self-adhesive foam seals are designed to be stuck on the back of the vents and replace the rubber seal on the bulkhead. That's why they appear to be the wrong size. Your early 110 (pre-92 with the hinged bulkhead brackets) had the bulkhead rubber seal as standard. Incidentally, you really need to replace that perished windscreen seal as well.

Are those seals any good? I did the exact same job last summer but put the foam seals on the vent flaps.

Can you share the p/n?