Because of now requiring an IFR equipped aircraft we could probably stretch to £30k between us,
Not a lot if you really want
full IFR, for that price I would say you are still only looking at a well equipped (probably not full IFR) Pa28 or similar.
For full IFR you really need an Instrument rating to fully use it so probably over the top. IMHO what you need to be well fitted out is, VOR/DME & Transponder whith mode C, from this you can expand to - GPS, ILS, ADF, second Altimeter. and that is the order of importance I would probably put them in, possibly swapping GPS and ILS depending on where you operate from.
