Crop rotation started by Turnip Townsend in the 1700s, if memory serves. Plot change of a basis of 4 year cycle, no manure prior to roots, personally use potatoes to start (usually reclaiming a derelict plot somewhere), brassicae,legumes,roots. Would be nice to stay somewhere to see the cycle round more than once!! Then youve got to shuffle the catch crops in, salads, onions/garlic 6 years ? Cant be too rigorous but I find the most important thing is to get a good start for next year, this year. Get the early planted bits prepared so you are not behind too far if winter lingers.