Thank you Clive,
If he won't allow you to examine this leg and he is dragging it, he is actually very likely to be painful. Cats are a prey species, so they do try to pretend there is nothing wrong when they can but when in pain will be resistant to handling of the sore leg. So, even if he is being stoic, we do have major concerns here. Especially since dragging the leg raises worries of bone fractures, hip dislocations, severe muscle trauma as well as nerve damage.
So, in this case, I must warn you that Woolfie may be putting on a brave face here. This level of lameness and his resistance to letting you palpate the leg are major red flags of pain and injury. Therefore, in this case, the best thing to do would be to have him seen urgently. His vet can pinpoint the extent of damage and get him started on cat safe pain relief (since our own pain medications are poisonous to our cats). If this is only bruising and muscle strain, then that will be all he needs. But if the hip is dislocated or the leg is fractured, he may need further treatment. And if his vet found severe nerve damage (a bit less likely if he can feel you touching his leg), then medical management would be indicated but if he failed to respond he could need the leg removed.
Overall, Woolfie isn't being truthful with you. Based on his signs, stress is likely but so is pain. Therefore, in case if you were keen to have him seen today, some veterinary practices in our country have office hours today. As well, I wanted to mention that most veterinary practices here do have contingency plans for emergency care for their patients even when they are not open. Therefore, it is worth ringing the practice. If they are open, you can get him seen today. If they aren't, then they will likely have a message to direct you on how to contact their out of hours service. And if you don't have a vet you can find one local to you, you can check the RCVS Register (HERE) to find your local vets or Vets Now (LINK) who are open all nights/weekends. In any case, if you wanted to get him checked out sooner then there are options to have him seen today too.
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best, Dr. B.