Realize that you are buying a very small diesel powered military vehicle with no power steering. If you don't mind that, go for it. If you want power steering, power brakes, quiet interior, smoother ride, a pleasurable drive, etc. then buy a RRC or Disco I.
You're going to spend almost $20k for a military vehicle that is in reality an $10-12k military vehicle. Yes it has been "refurbished" by the MoD but that is to military standards. You will likely not be happy with a 2.5 NA diesel in the end and will end up spending another $6k for a 200tdi/300tdi conversion which is in reality a $500-1000 engine.
If you do not have $60k in a checking account I would not recommend buying one of these. The entire market for them in the US is fudged. People overpay out the nose simply because they think they are rare vehicles that are worth that much. They aren't. I'm fairly certain the reason the imports change hands so quickly is because people realize how shitty they are. The ones that don't change hands are the Td5 builds that are actually nice to drive or the folks who build them to their exact desires. The casual I've-always-wanted-a-defender-buyer will be happy for a few months and then hate their life when they realize how much it costs to get the vehicle up to speed.
I owned 4 different early 90s/110s when I lived in the UK. You could buy them for $2k easy. The exact same $2k vehicles I used to buy with beer money sell for $15k over here even though shipping is only $2-3k. Do the math. You're getting ripped off if you aren't buying a plane ticket to the UK, Australia, or Europe to do the shopping in person. Don't think that a "dealer" is going to be any better. You can read on D90 that most of the sellers end up getting popped a year or two into business for being scummy and ripping people off. Just because it "drives and shifts as it should" or "goes into each gear fine" doesn't mean your transmission is in good condition.
That's just my advice it isn't supposed to sound harsh/hateful. I loved that Disco. Ended up selling it(when my wife said she wouldn't drive it anymore) and it's in Missouri now I think.
I think the 15-16k range for a tithonus/perentie is more realistic. The list price for the Tithonus at auction in the UK was around 6-9GBP. That puts the truck more in the 15-16k after import/shipping. I think the Tithonus is overrated since it's a regular one with new seats, exmoor mating system, roll cage, and special (awkward) top. Perenties on the other hand have the galvanized chassis, 3.9 isuzu, and the extended rear frame to put the spare underneath instead of on the back or hood. If you really want a military one, I would seriously consider flying to the UK and getting a rental car and going to Witham Specialist Vehicles and finding the exact truck you want. They have TONS of trucks and they'll let you inspect them before buying in person. The difference for the Tithonus versus a hand picked regular GS 110 would be negligible except in your wallet.
My best recommendation:
1. Plane ticket.
2. Hand pick your truck based off rust/bulkhead
3. Ship to the US
4. Replace engine trans with Disco running gear
5. Be happy that you spent $1-3k on a trip, $4-7k on a vehicle, $2-3k on shipping, and $3-5k on making it as modern as they can be with an EFI V8 and R380 or Autobox. $10-18k all in depending on who does your work. My estimates for the conversion could be off but I think those are reasonable.
