Hi LindaHi Pete
Your bus will take the same as Dazzer's, 5w20 semi synthetic. I'd also recommend you change the oil filter at the same time.
For the record, the early V10s run on 5w30.
Linda is absolutely right. She normally has the oil and filters needed (air and petrol in addition to oil) for a "decent" service". I can verify the actual process of doing the changes is easy - just make sure you have a drain tray under the sump that can hold 6 litres. All access to the sump and filters is a doddle.