Question about size of raised beds

Most plants will grow in most soils, so don't worry too much about having different soils.

We have 1m x 1m beds at school, because that's what Morrisons Vouchers gave us, but I'd prefer 2m long if I had the choice: you can pack more in.
A one metre bed is only big enough for one pumpkin plant and nothing else

Lol, I've started to reply twice, the first time agreeing with TS and saying go for the bigger one, and the second time saying no it might be easier to treat plants differently in separate beds! But on the whole I think I'd favour 'bigger is better', although I'm not sure you'll get a huge amount more in a 2m bed than 2 x 1m beds to be honest - and that pumpkin TS is talking about won't stay in its alloted space anyway, it'll crawl everywhere and need some severe discipline whichever size you buy!

In terms of rotation, I'd suggest it's good practice even in a small raised bed. You obviously won't have the same flexibility as in larger beds, but at least try to swop things around each time so you're not always growing the same things in the same part of the bed.

You may want to think about how you can cover / net or fleece one part of the bed without covering the other part too - eg you'll want to use a fine net (eg debris netting) over brassicas all year round, but not over beans or courgettes which need pollinators to access them. And carrots are best covered with very fine mesh or enviromesh to keep carrot fly out. So make sure you have some hoops to drape things over (I use electrical conduit), and a means of securing the polythene / fleece / netting at the base so nothing can get in.

It is really a matter of personal choce. If you only have limited space then I would go for the larger one, if you went for the smaller ones you are going to have dead space between them. Paths between beds are useful when you have a few but there is not a lot to gain when you are looking at either one or two.

It's six of one and half a dozen of the other - but if you're are paying good money for these I'd go for the larger one, simply because 2 x the 1m beds is likely to cost you more than 1 x the 2m bed.

Actually, I'd make the beds out out of pallets/planks/old shelves/items scrounged from skips etc.