Outer Limits 4x4 Board

Think I might have oil pressure issues in my hj60 2h got home last night only to find that the 60 had pumped all but a couple of ltrs of oil all over the engine bay and the ground. Removed the oil filter and noticed the top of it has balloned outwards it appears to have been leaking oil around the seal of the filter for a little while. Could it be the pressure relief valve?? Any other suggestions as to what may have caused this greatly appreciated. I live in the sticks so difficult to get a mechanical diagnosis. I use castrol RX super and service the old girl myself shes only done 259000.
Tony

This is pretty common, I believe its a stuck/faulty oil pressure relief valve. Try doing a search it has been covered a few times.