Anyway we can reduce our Swiss family health insurance which costs circa CHF 1,100 per month: Being English and Swiss, do Bupa or someone similar do a Global annual policy which we could use instead, whilst still being being officially resident in Zurich ?
Short answer, No
Longer answer, Swiss law requires you to be insured with recognised insurer if you are resident here. BUPA probably wouldn't offer you a suitable policy and even if they did it would probably not be cheaper than anything offered here for the same cover.
You need to stop trying to compare pounds and Swiss Francs. You live in Switzerland now so comparisons for this sort of thing are a waste of time. Have you checked on Comparis.ch to see if you can find anything cheaper?
The following 2 users would like to thank Medea Fleecestealer for this useful post: