Thank you everyone, some really great advice and feedback, giving me lots to consider. I went to the Camera shop in Winchester and tried the Swaro 8.5 x 42 and Zeiss (but not 8x56). On demo outside they seemed the same to me, maybe the Swaro very marginally better but not £300 better IMHO. Both well engineered bits of kit and easier to handle and use.
A wildcard option has also emerged as can get a very good deal on Steiner binos through a trade friend. They have Steiner Nighthunter XP 8x56 binos with porro prism for £770 RRP less trade discount etc. Not quite in the price or quality bracket of the Swaro or Zeiss but maybe a good enough option allowing funds to be spent on other kit and stalks. Looking at the forum, all seems positive on the Steiners but any comments welcome.
Thanks again.