With products like google glasses on the consumer market I wonder how long it will be before cheap (relatively!) technology becomes available to replace the £1M HMD? Of corse the HMD is much more complex and must be an order of magnitude more reliable but you get the idea.
As far as the F22 goes would it be better for the UK to just build more Typhoons? The RAAF has already tried to buy the Raptor but was blocked by the US congress. Who knows if they would change their minds if the RAF and the RAAF ganged up on them?