I wonder how much it costs to freight engines from you to me, and if we could both make a quid from selling them here?
On topic... I usually go for the devil I know. Doing up your existing head builds on the work that you have already done. If keeping the Jeep on the road matters, then you could buy a cheaper high mileage engine (with or without a vehicle attached) do up its head and straight swap. Less down time this way.