Helibelly
You won't find a plane that's OK for IFR for £30k, unless the seller is a mug, or is desperate to sell, or there are major bills just around the corner (which the seller knows about).
OK, before everybody has a go at me again, it depends on what is meant by "IFR".
It could be IFR in VMC outside Class A-D, which you can do in anything - that's presumably how flying schools are able to do IMC Rating training, even ILS into Class D airports, in planes which would not be legal for the same in IMC.
For real IFR (in IMC) in Class A-D, you need a lot of kit that needs to not only appear to function but it has to be calibrated etc, with various requirements like FM Immunity which old avionics tend to not satisfy. A few instruments alone will add up to £30k.
Unless you can take on board the ownership costs (which on a used plane can be pretty significant, with suprises here and there) it might be better to look for a share.