Shrapers

Greetings! The site looks great. I’m new to the forum and new to BMW’s and would like to waffle a bit about the first few I have looked at. I have decided I want a BMW probably e39 but have quite a low budget, maybe £2500. I Looked at a 51 530i 117k miles first up for £1995 The dealer said “this is a lovely car no problems what so ever” . I said “it's got a flat tyre” he said “when it’s cold sometimes the air comes out a bit”. Yup ok that makes sense. I went to drive it and as soon as I put my foot on the clutch there was a very loud grinding rumbling noise. I decided to leave that car alone. The next was a Y 530i 120k miles up for £1995 again. The biggest concern I had was an oil leak. It seemed to be coming from the right side of the engine under the inlet manifold and had covered everything. The engine management light was on and when we checked it was a “no.1 cylinder miss-fire”. The garage owner said it was due to an idle control valve which he was going to replace. It also looked like the previous owner had an Ocelot because the leather was so scratched. I decided to leave that car alone. I just got back from looking at a 51 530d auto 105k miles up for £2800. This one has some scratches on the body but other than that seems in excellent condition. I drove it and it accelerates smoothly brakes well, with no knocks or anything. Loads of tread on the tyres. MOT until dec. I said I would get back to them. Is my budget a bit too low to get a reliable e39? I’m pretty sure the first two are to be avoided? As for the last one I don’t know a lot about diesels so if anyone could give me any pointers on what to look for I would be grateful. Cheers Shrapers