Cheers for all the advice. I'm not getting notified of comments to the post, so thought it had gone quiet.
I haven't picked it up yet, but I've bought air, fuel and oil filters, new wipers, some 10W40 Delphi oil (is that okay, as it was the only stuff that was suggested on the website for the vehicle) and an alarm with remote start and wait for it......retro fit central locking! It's an ebay one from hawkcaralarm.com, with proximity sensors rather than ultrasonic, because apparently 90's aren't very air tight!
I'm just about to buy a cam belt kit, and found a video somewhere stating that everyone that has defenders changes the engine oil regularly, but forget to change the gearbox oil, so I think I'll get the stuff for that as well.
I was looking at posts about changing to a 200 tdi, but I will wait until the 2.5TD dies first. I may look out for one though, but will look at making it look tidy first. I think I will buy new doors and a new rear door, as they are the only things that are visibly rusting.
Then I will probably change the suspension and get some All Terrain tyres. If I get +2" suspension, what size wheels and tyres should I be looking at, and should I use spacers?
In terms of what I will be using it for.... I am going to stick the mountain bikes on the back of it and drive to a single track mountain bike course at the weekends, and use it to get to work when the weather is bad. At the moment the route is country lanes all the way, and they are the last to be gritted. I will also use it for dragging a massive roller around a paddock, and might try to drive down a few tiny lanes where cars daren't go, but nothing serious in terms of off roading.
That being said, I did read somewhere about joining a trip across the Sahara, but that's wishfull thinking at the moment! Probably need to see if the 90 can be driven 40 miles home first!