That's a Land Rover Ninety, not a Defender.
Also, I'd ask about the "2.5 TDI". There was no TDI offered in 1987 -- rather a 2.5 NA diesel. The 200tdi is also 2.5L, but wasn't offered until, I think, 1989. It's very possible he put a 200tdi in there, though, as it's a relatively common swap...