Gentlemen, many thanks for all your suggestions and comments.
Because the cars in Spain, its difficult to try these straight away, however the injector cleaner has to be worth a try, and is relatively inexpensive, so will do that next time we go in a couple of weeks.
The lift pump suggestion seems logical, but I wouldn't know how or where to fit the resistor, so I will need to find a reliable auto electrician over there, that could be a bit of a task in itself.
As for the engine surge, and stalling, I think I agree that this is a separate problem. I did find another thread on this site from someone else who had the same problems and he fitted a new injector pump which apparently cured the problem, although a trifle expensive. I think I might see how this progresses for a while, the car is only a run about, and you can compensate for these nuances with driving style, even though this is all a bit annoying.
Yes, the car does need a good service, but I don't feel this alone will cure all.
Once again, thanks for the help, and keep them coming if anyone has any further suggestions.