Seat Leon is all the best bits of the Golf (reliability, economy, strong engines) with most of the crap removed (Leon actually has steering feel, and goes round corners well).
Why does the interior bother you that much? Surely functional is better than pretty in a sub £3k car?
FWIW you should get a tidy, sub 100k mile 110bhp SE model for less than £3k, with a FSH. This engine is the most economical of the bunch, and probably the most reliable. It also still easily remaps to about 140bhp very readily.
An alfa with 154k miles on already though? Less heartbreaking to burn the money I’d say! Your Peugeot I’d not be surprised at the milage, those old 1.9td’s were strong engines that went on a long time, I know of cars that had more than double your milage.