@HorseyLady, it's nice that your surgeon says all is well with your hip. Regarding him saying that you don't have to see him for a year -- here in the US, in the two orthopedic practices where I have had surgeries, insurance give appointments with the surgeon's office at 2 week, 6 weeks and 3 months of a surgery. I would think that, in your situation in the UK, if down the road you have any remaining concerns, that you could call and see that surgeon again. If not, because of their rules, then perhaps you could see your GP. I would think that if your knee does not get better in a reasonable amount of time, that would warrant an appointment with someone. I never have any problems with my knees post surgery, beyond what was wrong with them beforehand, anyway!
Also, I do not understand your surgeon's comment about waiting a year to do the other hip. When a hip needs to be done, it needs to be done. You can't just arbitrarily assign a date without knowing the state of the hip joint. So i would say that if your non-surgical hip is painful, then it should be assessed, regardless of how much time has passed since the THR. All it usually takes is an x-ray, and that shouldn't be hard for an orthopedist or GP to order. I've read about plenty of people on this and another forum who have THR's quite close together.
That's my 2 cents, anyway! Wishing you all the best as you recover, and hope you get relief from hip #2 soon!