Sounds a good plan overall Darren; you have thought about issues at least.

I am not sure that I would spend the ratio of 2000:1000 on the bike Vs the accessories! I would prefer to put more into the bike and use cheaper bits and pieces, including maps in place of GPS.

I reckon you will find a suitable bike between now and January; I suggest you take a look at the KLE500 on here - loads of information about it in threads in here and there are dealers in the UK selling them brand new for about £2800 or thereabouts -- second hand they are not much cheaper, presumably because they are such good value new.

Also, your overall budget sounds like plenty for your travel timeframe (I am assuming you will use cheap accommodation) so maybe you could put a bit more towards buying the bike.

What I was getting at in that last post was to look for a type of bike rather than a particular model; don't limit your choice. Do a search in, say, ebay for "trial bike" and see what is up for sale + check out other places such as Autotrader for every type of bike, not necessarily a trail bike, and keep watching the for sale section in here.
Another guy on here is travelling on a Honda cbf600 for example and there are lots of them on the market; no problem because you don't intend to get off the beaten tracks.

Good luck with your plans,

ps There are more DR650s for sale than there are DR750s, have you noticed?!

__________________
Dave