I used Wick for years and always found it most hospitable with plenty of parking and quite enjoyed the ride down the river to the entrance. It has the added advantage of giving your engine a flush in fresh water. Watch the channel and yes, the entrance can be challenging but, during the summer, it is normally well and reliably marked. Alun is obviously the meister on the entrance and yes, he uses Mudeford slip which is only a few yards from the entrance.
Terry.