Hey Ben, welcome back
i think you're bang on the money with your spending estimates.
some people are getting ebay bargains now for 700 - 800 quid.but i'd say they are still reasonably rare finds & usually higher mileage (still not high as such), possibly a bit tatty around the edges but perfectly rideable.
1700 - 1800 should imo get you a nice low mileage fazer 2001 onwards without too much searching.probably still quite original but as a result will possibly cost you more money if you fancy the usual upgrades.(remember a low mileage bike will probably not have had it's front sprocket nut upgraded to the new one!)
1000 - 1300 will get you a myriad of fazers usually 98 to 2001 models with reasonably high or normal mileage but not the mint originals, they'll often have had some upgrades such as stainless down pipes & end cans, k&n's, renthals etc.
all my personal opinion of course from general observation.
winter will obviously throw up some cheaper prices.
hope that helps
fras