What grade of oil does your handbook recommend? Stick with that and you'll not got far wrong. I would expect something more like 10w40 to be recommended as 5w30 seems a bit on the thin side for an oil burner to me for use in the UK but use the grade that your handbook recommends.
thanks, I've ask a couple of people and have had mixed replies. The oil is from a ford parts dealer shop and I was told it can be used in their diesel cars.. so I thought I'd ask for opinions on here before I buy. I hear tesco are doing 5 litre oil for £5 or something really low..