Interestingly enough my experience was exactly the opposite. Potters can seem expensive but if you take the time to talk to the chaps back where they keep the rifles I've always found them to be friendly and accommodating - even though I was only ever able to look at the cheapest of the secondhand rifles. Half the time with a pushcair as well. Andersons in E Grinstead on the other hand were rude, dismissive, expensive and ignorant - basically couldn't be bothered with me (and spoke a lot crap) the 2 or three times I went in there so I stopped bothering.
It's been 3 years at least since I last went to Andersons so if they have turned themselves around that's all good but I can't recommend them on the experience I had, unlike Potters who are great, but you do have to establish yourself a bona-fide rifle shooter.