Hello Phil,
That is not really all that many miles, although if the engine has been neglected then the wear could be far more than it should be.
Is your oil pressure transmitter a stout metal canister or a large nut with a black plastic cylinder sitting atop? If the latter, these are notoriously unreliable, so the reading is quite likely incorrect.
Areas that can result in lower oil pressure are worn rocker shafts, heavily worn camshaft bearings, heavily worn main bearings or caps which are coming loose, significant scoring inside the timing cover where the oil pump gears reside, significant scoring of the oil pump front cover where the gears spin against. A partially blocked gauze strainer on the oil pickup within the sump will also see a reduction in oil pressure.
As Harvey said, your best bet is to drive the Rover. Record what you do and when you do it, look for changes. You could well do another 88,000 miles and see no untoward changes at all.
Ron.