Hi again sparkly :)
If you're planning your new plot, plan it around you, the veg you want to grow, and to take into account soil variations.
After making a rough plan, take stakes, scissors and string, consider orientation, where you want your shed, greenhouse, paths, compost bins etc. Whoever had the plot before may not have followed a tall/short rotation, (North and South), or have the right areas (we hardly grow any spuds, so I include tomatoes in 'solanums' for rotation. If your soil is in good heart, a season's adjustment shouldn't hurt it. If the worst happens and you find you have e.g. onion rot on part of your plot, the only way to find out is to plant onions there - and 'red flag' the area for the coming season ::) I'd suggest staying with string and stakes for at least one season, as you may want to adjust your layout in the light of experience.
A bit like fitting out a new kitchen when you've bought a house - yes, ideally you'd build it around existing water inlets/outlets, but really you'd design it to meet your needs and consider yourself lucky if the plumbing was in the right place. My advice would be to plan from scratch. Good luck!
SSx