Lookie here,
As been pointed out in various threads the "Oil Police" have already thought of that one. Sellers have to keep records, and if they spot a dodgy person - YOU - and not stop or report you, they'll loose their license.
If you only need a small quantity at a time, then nobody's going to bother too much, if you use a lot are you going to be bothered to lug lorra, lorra jerry cans around; I think not.
Easier to go down the domestic exemption route.
Of course you may enjoy banging you head against a brick wall....
Instead you could try driving your tractor a helluva lot between now and November 1, and then not using it anymore?
Got the point?
Big Brother Gordon has been there before.