According to my service manuals, for the UK you need a 5-30 SAE oil for the engine (but you could get away with a 10-40 synthetic), the transmission uses DX3 oil (ditto for the Power steering) and the coolant should be a decent glycol based coolant mixed to the correct ratio's as listed on the bottle. (Think at least 5 litres of coolant concentrate and top up with clean water.)
DO NOT SKIMP ON THE OIL QUALITY IF YOU VALUE YOUR ENGINE!.
Hiaces work their diesels hard, they run very hot and put alot of strain on their oils and coolants, everything is working at or near its limit.
If you want it to live long and prosper, use the best oil you can afford and seriously consider an oil cooler, even in the UK. Long, hi-speed motorway runs do the engine and its oil no favours.