Sydenhams Ltd Abingdon

VERY helpful staff. Even to a non-builder or DIY person like me. Easy to find what you want, and they will be honest with you about the price and if it is cheaper elsewhere. Good guys there.
They even advise me about something I wanted to buy, when it was not what would solve me problem, saving me wasted money. They were also honest and helpful about paint - when what I wanted would be cheaper at Homebase. They have given advice and service above and beyond what was required.

VERY helpful staff. Even to a non-builder or DIY person like me. Easy to find what you want, and they will be honest with you about the price and if it is cheaper elsewhere. Good guys there.

Huge selection of stuff - and expertise. Great tool selection upstairs too. While it's tempting to just head to Screwfix, Sydenhams compare pretty well price-wise, and have the benefit that you can ask questions and can actually see what you're getting and offer it up. If you're buying individual parts (plumbing, screws, etc) you'll likely find them far cheaper than Homebase and B&Q too. They also do paint mixing and will cut wood to size - they're a hugely helpful place to have locally.

If they haven't go what you're looking for then they normally know where you can get it.
Nice guys and really friendly.