Convenient and well stocked
Halfords is both convenient and well stocked.
It's the perfect place to go for accessories like bulbs etc, not the cheapest but parts are available off the shelf so worth the small premium.
Their leisure / bikes section is also extremely good value for money too.
They loose a mark for a few recent let-downs.
First, ultra-brilliance bulbs, only seem to last 6 months, expensive to replace these so frequently!
Second, bike assembly, a little bit sloppy, worth checking things over yourself as well before riding if you don't want to have an accident!