Thanks for your reply.. Happy New Year!
Just waiting for the garages here to re-open and I'll start over again... There's a place in Airdre that sells reconditioned TD5 engines (they have a 10,000 mile warranty) but I haven't the foggiest whether that is good/bad or indifferent. My lack of knowledge when it comes to the actual nuts & bolts of land rovers is glaringly obvious so I have to put trust in those that are experts. My learning from this chapter is that not everyone who works in garages are great mechanics - Duh! I'm really hoping the guys who have Gemm 4x4 are ace.. They only deal with Landrovers, seem to love them (this is a big thumbs up in my book) and have a good reputation. My local garage aren't so enthusiastic, they look at it and see an "old" vehicle, where as Gemm see "TD5 Defender, great "..
When it comes to changing the bolt, I'd ask for it to be done just for peace of mind.. if the one thats there isn't flawed then a good garage (?) will let you know.. Can't do any harm I guess.. Joining this forum has also been good - I'm going to get a oil gauge fitted - advise given here and something I never thought about before. The oil warning light on the dash isn't really fit for purpose.. If that goes on when you're driving, it would appear that you have just trashed your engine quicker than you can click your fingers..