Quite a few options used for £350
As mentioned the 77k and TX200 also the Walther LGU
Is your preference under lever?
As I notice you also have a HW95K if you went break barrel there’s the HW80, HW90 (if you fancy some rammer fun), HW98, HW99 plus many others like the Walther LGV, century even some Diana’s 280 etc all should be doable with that budget used but some harder to find.