Ooh, how exciting! London is a great city, it's so interesting and bafflingly busy to a country dweller like me! Lol. There is generally free wi-fi in cafes and places like McDonald's (of which there are loads :/). The weather here in all of England has just been the wettest April on record, and we're set for more up until June, so pack so waterproofs! It's not particularly cold though. However, having said that, today is a scorcher so bring nice clothes too. The British weather has its own agenda. Hope you have a great time!