I had an excellent experience at the walk in centre.
I had to wait a long time, but I was warned of that because, as I knew, my case wasn't urgent. I suspect that they prioritise on the basis of urgency, which is why it may be that people who arrive after you are seen before.
I was worried about having to renew the parking. However the person at reception told me that once I had bought a ticket I didn't need to worry about renewing, as those checking the tickets know that people often have to wait a long time. Check though please rather than taking my word for it!
The doctor (can't remember the name) was the best doctor I have ever had I think in 38 years. This doctor was very kind, took time and interest and listened and gave good advice. I wish this was my regular doctor!