The Air Arms S200. Cheap, reliable, ('controversial' looks - either love it or hate it), and you can upgrade it to a multishot for 60 quid. It's also small and light. Could even make a refreshing change from the HW100 when you fancy something a bit different. Another alternative is the BSA ultra multishot which is even smaller (I think). It's so small however that shot capacity suffers. Yiu'll only get about 35 shots = 3 mags worth. Hope this helps.

Chris