Absolutely go out and buy so long as you're prepared to spend money on it. But do check all the usual Range Rover places for rot first. An M reg should be the "soft dash" version so an updated more plush interior in the classic shelled RR. Check the rear floor, chassis, bulk head, rear arches, A + B posts, sills, rear tailgate, and everywhere the aluminium panels meet the steel frame as it causes galvanic corrosion, suspension, exhaust and mounts, sun roof drain tubes and I'm sure plenty more. Check, check and check again but for that sort of money you're probably looking at scrapping it when the mot runs out unless you're willing to take the time and effort to fix/restore things. If you can work on the car yourself will make a serious difference to running the car as parts are expensive or find a good garage with experience of older models. eBay will become your best friend for finding bits and pieces.
Having said all that and now probably thinking you'll pass on buying it...I bought an end of the line 93 "hard dash" model which had a few run out luxuries which should have been scrapped and god knows how it passed the mot before I bought it, BUT, I went in with my eyes open noted all that was wrong with it and bought it for a couple of hundred quid and set about fixing it. I'll have had it 3 years next feb and don't think i'll ever sell it. I do about 3000 miles a year in it and it puts a smile on my face every time I use it. It's not perfect by any means with dents and scars collected over the last 20 years but very refreshing not to worry about someone else knocking it or where you park it. Mine has been totally dependable passing it's MOT's every time without advisories. It runs about 24mpg on the motorway and drops down to about 18-19 combined. It's a completely different way of driving and you'll be amazed when you drive routes you know, how much you're missing out on by sitting so low in the golf. Other drivers don't have issues with you either being sat in a big 4x4 unlike some newer models.
As with most things do your research first and you won't go far wrong. I would suggest spending a considerable amount more on a good car first so if this one turns out to be a dog there will be more out there but be quick they are running out and prices for good ones are rising. If you fancy a punt and have a few quid to throw away find an older 2 door model which are the ones to hang onto and can go for serious money.
Ps If you take it for a test drive, make sure you do a three point turn and if it has trouble with tight turns the transfer box is binding which costs a fair bit of money to fix. Check the high/low transfer box works smoothly and it doesn't clunk into reverse.
Good luck
