I have no local experience to your area.
Curry's / PC-World appear to be one of the UK chains, and Maplins for some stuff. They might have some helpful or unhelpful advice but you can use them as a pricing baseline (cursory research tells me they are overpriced), so seems about equivalent to Best Buy and Staples here across the pond. Online retailers seem to be a popular way to go there.
There are little shops around that would be helpful and although selection might be limited, they are often priced reasonably and have knowledgeable people. One I found was "The One Stop Computer Shop" in Sherwood Nottingham... I liked this review from a confused customer: