The sort of car desired here is very rare these days. When they do come up its usually a known used omega dealer that finds them. Not so much DK anymore, but Roger Bhuden and 7star have had this type of car lately.
I guess they have contacts at dealers that punt out chopped in omegas.
I'd guess they buy at 2-3 k and wack a hefty mark up on it to 4-5k. Then be prepared to sit and wait. They all sell in the end.
Having said that insurers won't pay out much more than 3k on any standard omega these days. Any extras would mean an addition to the premium.
Lpg fittng. 1500 to 2k depending on kit professionally fitted. Several of us have fitted stag kits diy for about 7-800 quid or so.
Buying privately, and being very patient, you could potentially achieve your goals for about 3.5k with lpg fitted diy. But you could be waiting a long time for the right car and face stiff competition when it does eventually come up.
I paid 3k for mine at auction with 70k in goid nic. But it still needed a fair bit of work. Although that was a 3 years ago now. I think
Ps Thanks to Josh Wyatt for his help at the Auctions.