Ah The Classic British Auster.
I guess you must have your own reasons for looking at one. They are halve the price of a super cub, seat more than two and are side by side seating.
As has been said, the British in line, 100 hp Cirrus Minor (J1 Autocrat) or the 135 hp Gipsy Major (J1N, Terrier, AOP 6 ect.) can be the weak point compared to an american engined aircraft. But certainly not stumbling block.
There are some Lycoming powered ones, but not as many. These range from the 135 hp 0-290 powered war era Mk5's to the later Beagle like the 180 hp Husky (but these are rare and supercub money). There are three J1's with 160 hp Lycomings retrofitted, plus my one (the only one on a pfa permit), but you won't prise these away from anyone.
So for costs you can by a 100 hp autocraft or a 135 hp Terrier (or AOP 6, with the extra lift devices) for about £ 15/16 K.
If you like the idea of a AOP 6, in military colours. I think Chris Harrison, near Oxford is still seling one for reasonable money. PM me for his details if you want.
Regards G-AHAP