In the last 3 years I dealt about 10 times with the guys at Model Hobbies UK: mostly from their internet store, and a couple of time from their Ebay store.
Their website is well organized, with many different categories where to look at.
Products are presented with one or more pictures. For each items it is stated of on stock or not.
You can register, and so have a record of all your past orders, or create your wish-list.
The range of products offered is impressive: from kits of all the brands (also short run kits), to the paints, the weathering products, tools... whatever you are looking for, good chances are to find it here.
The service is excellent: after placing your order, you are always informed about its status (processing, shipped...).
Last but not least, shipping costs are very reasonable.