one thing i should say is DONT RUSH, series 2a are going up in price, while the series 3s seem to be holding there own, go look, poke about, ask questions, drive, look, feel etc etc etc, take someone with you and dont let distance be a problem to get the right one;l
use your head not your heart, any series is going to cost you time and money to keep on the road and in decent running condition.
i have seen a series advertised for £19,000 (obviously dont want to sell it) right down to about £300 for a complet dog requiring every part replacing.
the bulkhead and chasis are the bits most prone to rot - the chasis easly repairable with a decent welder but the bulkhead a lot harder to do unless you can get the fixing kits for them, however for 250-300 would buy you a decent bulkhead, (£600 ish a galvanised one) but remember a car/vehicle/van/landrover is only worth what someone is willing to pay for it and some people are putting prices right up hoping that they can get over the top money to go buy a dog and have money to do it up... good luck with your search and hope to see some positive news from you...