ooh, I can help with this one! I've been lactose intolerant for years, and have dealt with it a number of ways - from avoiding (most) cheese and milk to taking the lactaid pills to using nondairy substitutes, and at the beginning of the year I decided to work towards being vegan (have been vegetarian for about fifteen years and decided to step it up a bit - I'm not there yet but I've eliminated the remaining bits of dairy in my diet now).
I have only done a bit of investigating into the dairy subs in the UK, and I don't know how many of the old US products I had are over here. If you can find Tofutti it's worth a try - their Tofutti Cuties (mini ice cream sandwiches) are super yummy. IMO all the soy/rice/almond/etc milk brands taste slightly different, so it's worth trying a bunch to see if one has a flavor he likes. Some are sweetened, some are 'natural', some are chocolate!! I saw some smaller containers at Waitrose last week, so you can try a few different ones without having to fill your fridge with liter containers. I use Pure Soya brand margarine - it tastes fine on bread and cooks like regular butter. They also make a cream cheese product which I just tried and found FANTASTIC. I'm going to be looking to see if they have other products to try.
The advice most people are given about fake cheese is to avoid them for a while after quitting dairy, and then experiment with some different kinds, and to NOT expect a super dairy taste. it's just not going to happen. There are some types that melt well, and some types that are better for sandwiches. If you want to try these, google for "vegan cheese review" to get an idea of how people have used the different brands.
I also have a cookbook called "the un-cheese cookbook" or something like that - my cookbooks are being shipped and aren't here yet - which has a bunch of nut and nutritional yeast based recipes for cheese-like sauces and such. I've only tried a couple of them, and they aren't mistakable for a dairy meal, but they're certainly tasty enough.
I can't make a yogurt rec - when I ate it I always preferred thick yogurts, full cream or greek style, and I haven't found a soy one that has the mouth-feel I'm looking for. So I'm going without, though I try a soy yogurt every once in a while and usually find it too runny.
Good luck! Honestly, it's not all that hard to live dairy-free, and there's a lot of good products out there these days.