OR...
Terry could take his OMEGA to a garage, have the car checked ,find the coolant leak,find the exhaust leak and get a price 
have the garage check it over as far as the next MOT goes 
many local mechanics will come to you to do work.
If the cost is reasonable ,Terry could be driving a car he's comfortable in , familiar with , an OMEGA
yes the OMEGA would be worth peanuts and repair cost could be 500 quid , so what  

better than spending 5 grand on a euro sh!tbox that he's not familiar with, won't feel comfortable in 
Just because a car is newer does not mean it won't have exhaust leaks,coolant leaks or very expensive repairs 
buying any car OR owning any car is a gamble ,choose wisely ,low mile examples that have been loved ,serviced etc are a better bet than a newer car that's been abused 
IF the Omega IS past it , Terry has tried and/or owns a vectra c and various astras , low mile ,cared for examples can be had IF you shop wisely , again , putting Terry in a car he's familiar with, comfortable in 
there are still some GOOD ,cared for OMEGAs out there, sadly Terry is not keen on auto gearbox transmissions 
maybe Terry should try one 
I've lowered my standards and drive an auto  
 
 