I used to work on Wrexham Central retail park when it first opened (always thought it was a rubbish name too, not very central at all). First I worked at Dunelm Mill, then at Au Naturale before moving to Nottingham. I used to use th car park regularly for free when I was visiting town and all I ever did was to place a carrier bag of the place I worked on the dashboard of my car. This worked 99% of the time – except once when an over-zealous car park attendant tried to give me a ticket while I was at work and I managed to convince him that it was stupid. I was even in my uniform and he didn’t believe I worked there.
Dunelm Mill is good if you know they have something you want, but other than that, I think it is vastly overpriced. Go to the markets instead, get something made by a local who will certainly appreciate your custom more and it might just make the difference between him or her making any money that day!