I did one of my mystery shops this lunchtime. It was perhaps predictable that lunchtime at month end and week end would be a bit slow.
I arrived at 12.10pm. There were 6 or 7 people waiting for the meeters and greeters but it only took a minute to get past them so I got in the queue at 12.11pm. Inside there were about 50 people waiting which is quite busy compared to previous visits. There were two cash office windows open with two customers being served and no-one waiting. The perking permit queue (I always put myself in this queue) was 6 people but it went up to 10 whilst I was there.
I was seen at 12.34pm so had a wait of 23 minutes. Long but in no way hideous considering it was three times over a bad time to visit. There were 5 staff covering parking with two off for their lunch break.
On my way out I used the loo. It was totally acceptable. Certainly as good as or better than the typical work place loos I have ever used. Certainly better than most pub/restaurant loos.
If you want to avoid the queues try paying PCNs, buying permits and vouchers online here. I just ordered some vouchers. Very easy. I am afraid I have had cause to pay a few tickets on line recently. Again, very easy.
Update: My vouchers arrived Wednesday morning (4th November). Less than three working days. Not bad.