Oh a million questions. Most of them have answers already on the site somewhere, but here goes with some ready-packaged (and condensed) ones. Helmet. The important thing isn't how much money or how many sharp stars, but how well it fits. Try some on in a shop and ask advice from the guys who work there. £50-80 should sort you out. Jacket, trousers. Textiles are going to be most flexible for year-round commuting: they have detachable linings that can be removed in summer, and will be reasonably waterproof. You can wear textile trousers over normal jeans (just make sure they're not a snug fit). Kevlar jeans on their own are too cold for winter; mine stay unused until May.The stuff from Triumph outlet is good, but I think you don't need to spend as much as £100. There are usually plenty secondhand on ebay. Gloves. Basically yes. Just don't get summer, racing or motorcross gloves - they will be too cold (and motorcross won't give much protection). Boots. Motorcycle boots that come half way up the shin are ideal. They will give better grip and offer better ankle protection than most casual boots. What bike? To be honest, for a 4 mile commute on 30/40 mph, I'd be on a push bike, but I guess that's not an option. A CG125 or a YBR would be great. But for £700? I think you might find a bike that needs a bit of work at that price, but then you'll need to spend time and money sorting it out. A 50cc would fit the budget, but mightn't be what you're looking for although it would do the commute fine. I won't give you an opinion on Chinese bikes; others here will.