Firstly - many thanks to everybody who has replied...much appreciated.
To Get_A_Grip - apologies if my post upset you - I know constant postings about equipment advice can be annoying......BUT considering I only joined the forum yesterday and it was my first posting...initially I did find your posting quite aggressive and insulting but then I'm just oversensitive.
I have spent many months researching equipment which I thought was obvious from my posting. Anyway moving on....
Budget - I don't really want to spend more than €5,000 - that's for body, lenses, tripod/head, flash, filters and bag.
Having read the comments, I will probably ditch the idea of the 1.4 extender. I just hope 100-400 x 1.6 is enough for wildlife. Only other affordable option would be a Sigma 150-500 or 50-500 but not sure how they compare for IQ or AF.
With regard to landscape I had thought about the 10-22mm but was hoping to try and get a lens that would cover landscapes and bridge the gap upto where the 100-400mm starts.
I have no plans to go FF in the forseeable future so it is good to see the 15-85 getting good comments. If IQ is as good as 17-40mm L then it might be the way to go.
My internet research had thrown up mixed reviews for the 10-22mm so it is good to get good feedback on that one here from end-users.
My interest is definitely split 50/50 between landscape and wildlife (wildlife being birds, mammals, insects, plants, flowers - hence the macro requirement as well).
Lastly - maybe you can offer opinions on this - some friends have ditched their 100-400L lenses and replaced them with 300L F4 combined with a 1.4 extender - apparently this combo gives better IQ?