Changed the oil filter and refilled the engine with oil. Turned it over for a while without ignition and the oil pressure lights went out, all good.
I even remembered to connect the wideband controller before trying to start the engine (as an unheated sensor apparently doesn't last too long!)
Went for a full start and it works perfectly. Just let it warm through for today.
Only a couple of small lockwiring jobs before it can go back on the road, although with today's weather, I am not really missing anything!