Hello and welcome to just answer. The first thing that you need to do is to have the oil pressure tested to see if there is a low pressure problem or if it's just a switch problem.
Have arranged to have oil change, flush and new filter.
I would still recommend the oil pressure test before going too much further though, Some of the diesels had an issue regarding the oil pressure pumps failing.
Oil pump failure means dropping sump etc to get to the pump - is it worth it for a 2005 motor. Probably expensive??
If you so have a oil pump problem it is usually the small shaft that drives the oil pump that rounds off and fails. You have a few options with this and the cheapest it to replace just the shaft but it will eventually fail again. This requires the sump down and the small shaft replacing. The other option is to replace the oil pump and the balancer shaft set. The balancer shaft set is the usual end that rounds off and this will cost you quite a lot of money and from memory you'd be looking at somewhere around £1000 for the job.
OK many thanks for your comments. I guess I will try the oil change first and see what happens. I may have to bite the bullet though.
If oil pressure is OK what needs to be done to stop the Warning Light?
You are welcome and I hope the oil change helps but I think you will need more work to fix the fault, If the oil pressure is all good it could just be as simple as a new oil pressure switch or even the wire just rubbing somewhere against the engine causing the light to come on.
No further information required.