I have driven up from Southampton to Shrewsbury twice (I have a very understanding husband who allows me to make a weekend of it!).
We have had a featherbed for a tenner and loads and loads of craft stuff and Birkenstocks and odd bits of jewellery. But beware: although the craft stuff says "do not open" on all the packets, it's worth asking the friendly staff to do this for you. Often, people kick the arse out of the 30day mbg on craft and have used a huge amount! That said, I have got some fantastic fantastic bargains, but am just discerning about what I buy. Also bear in mind that all stock at the outlets also qualifies for the 30day mbg, so it's win win, really. I took some stuff back to our hotel, thought better of it and took it back for a refund next morning-no hassle, no questions, just really friendly and helpful staff.
Can't speak for Warrington-have never been.