Some don't-buy's from me:
Don't "stock up" on nappies too much, as apart from how quickly they grow out of them, you don't know which ones will fit your baby till you try them, they are all different shapes so you need to find ones that work for your baby! So don't get lots of the same brand. Same applies if you decide to try washables, unless you are getting them free/very cheap of course!
Don't buy nappy rash cream until you need it, you get tons of free samples in the Bounty packs and similar and some babies just don't have much trouble with it. I still have loads left!
Also don't buy lots of toiletries if on a budget, we never used anything except baby bath and later on, a little baby shampoo occasionally. And don't go overboard on cotton wool or you will have loads left when you finally go "sod it!" and reach for the baby wipes!
Hooded towels are sweet and handy, but they are quickly grown out of so you may prefer to get some "nice" ordinary (bigger) towels they can keep on using for longer, instead. (I was a bit sad when DS got too big for his!).
Don't buy many top sheets and cot blankets if you are thinking of using sleep bags later, as you won't need them unless baby is relatively small. On the other hand, if you are thinking of swaddling (we didn't with DS, but it was really good for DD) you will need a few big-enough sheets, or a couple of special swaddle wrap thingies.
10 changes of clothes sounds generous, especially as you WILL get some as presents (and if you have a big baby, they may barely wear Newborn size, as I found with DS..) Scratch mitts are a waste too, again you are almost sure to get some in presents (they are always included in those baby sets) but baby will prob just pull them off anyway. What you might want though is some sort of coat or light snowsuit thing (even if it will be a Summer baby).
Steriliser and bottles you will need, but I should think you can get them cheaper, or even get steriliser on Freecycle or something - a microwave one is really a very basic thing, just a container with a rack and a good lid, so no reason to spend lots. Baby carriers are also good to get secondhand or on Freegle.
Mothercare do a great bath support, a metal frame with terry cover like a hammock. Works from tiny-baby till they can sit, costs around £8 and much better than a baby bath.
You WILL need a change bag, the Boots free one is actually really handy though and loads of my friends relied on it for a long time. Later on it is nice if you can treat yourself to a fancy one though, esp once you start weaning and are carrying around more clobber, as the Boots ones are quite slim (which is an advantage at first though!).
Sainsbury's basics nappy bags are 9p a pack, or less when they have offers on, and I find them at least as good as more expensive ones and better than some!
Oh and you will prob want a baby gym thing (mat with arches & hanging toys), but if you start looking now you can prob get a good price on a nice one, or ask for it as a present.
Don't forget a decent thermometer (not crappy forehead non sticky thing) and some calpol - don't wait till you need them at 2am! Also baby nail scissors/clippers.