I'm with MrYou in going the mil surplus route at the minute when it comes to stalking clothing. (I have 2 Musto coats and a selection of other stuff as well but am finding the mil surplus is what is going stalking every time)
My hint and tip is to get yourself a British army surplus windproof smock in DPM which is the older material, having now handled the newer MTP windproof smocks they seem to be a different material and I'm not yet convinced they will be as wind/waterproof. I've seen the DPM windproof smocks go for £7 new on ebay, though £15 or more is more common, don't pay extra for ones that claim to be SAS or similar and I like to go for a reasonable chest size as they seem generous (I'm about a 38 inch chest and wear the 96cm NATO size smock which leaves plenty of room for layers under) but usually select a size too big in height terms so the jacket becomes 3/4 length on me, sleves have velcro so you can tighten them so they don't feel as if they are long. Wash some waterproofing into it, nikwax make the most commonly used one but there are others. Don't wash it in detergent but use the nikwax "tech-wash" or similar to wash it before you proof it. Try this out and see how it works for you. Despite my expectations mine hasn't leaked yet through a season of stalking here in Ireland plus a few weeks fishing in the Hebrides, though I haven't had a day of solid horizontal rain which I'm sure would beat it.
However, this isn't 100% waterproof and I would expect that it would eventually leak on a very wet day. To solve this situation buy a German flecktarn gore-tex jacket off ebay for £10ish for a good one. This jacket is pretty light weight and will actually roll up and pack away into its own hood if you want to drop it in the rucksack. The German sizes seem fairly tight so be careful. (The British DPM gore-tex jacket would do just as well but they usually seem to cost more) Most mil surplus gore-tex jackets have little in the way of pockets for a good reason, the German one has two small side pockets.
On a very wet day wear the flecktarn jacket UNDER the windproof smock to ensure 100% waterproofness. This means that you retain all your pockets etc. with no need to move stuff about as you are wearing the same jacket on top. This might sound like a strange idea but try it and see what you think, I'm certainly a convert. The pockets in the windproof smock are, certainly for me, ideal for stalking.
Going that route you can have good stalking gear which is as waterproof as you will get for £30ish.
The one slight down side is the military camo patterns which I will confess I'm a bit uncomfortable with wearing as I'm not a soldier and I'm not pretending to be one. However, for the most part no one sees me and if it was a big issue for you the windproof smocks do occasionally come up in plain green. The DPM camo pattern can also be a bit dark for a lot of UK stalking though it might be OK for dense conifer forest but I don't find, to be honest, that my stalking relies much on camo and favour the smocks for comfort, design, pockets etc. The new MTP pattern is much lighter in colour and I suspect ideally suited to woodland edge and even open hill stalking it is also said that the dye in it reflects heat from the sun so making it cooler to wear in summer but I've no idea if that is true or not. MTP pattern gear is still a little expensive on ebay but it gives the option to have the same smock (i.e. pockets) in another lighter colour pattern if that would work for you.