Hi
Just a few thoughts from my own experience of restoring my 110 and my sisters 109, wifeys mini and a merc 190.
Firstly, despite access to a comprehensive workshop, (I have too..) you may find you run into trouble with a tight deadline like that, there is a saying 'Faster, Better, Cheaper, pick 2'
To do your project in a few months will ideally mean you need to spend more on your car in the first place, BTW the tax exempt ones fetch a serious premium! and you'll want fairly deep pockets to get parts etc... my sisters 109 cost £500 to buy and has so far cost a further £600 in parts.
Also at the risk of being shot, and despite being a die hard landy fan myself, are you sure a series 3 is what you want? daily driving will get expensive in fuel and other running costs, you might also want to get some insurance quotes too, when I was 21 I was quoted £5000 3rd PT&T to insure my 110 for £4000!!!!!. A lot of people get a cheap car like a clio or something and leave the landy for playing at the weekend, also its less of a pain when you break it offroad and can still get to work on monday!
My advice for what its worth would be to get a runabout to use daily and your series 3 then you are under no pressure to restore it, you can then take your time and do it properly, and end up with a really nice toy at the end
Mike