My hubby is bril... He made us a new raised bed today, one that fits with the second cloche we bought. He used decking boards from B&Q, like this... they were 2metres 40cm in length.
He had to cut them in the car park so they would fit in the car :-O...(that's not our car in the background by the way, we really would have to cut the planks small to get them in that!) He simply cut a 3 foot length off each plank.
Anyway, we got them home and he made the rest of the cuts to make a 3 foot square raised bed... so eight pieces of decking, with 4 pieces left over.
He drilled and screwed the planks in place, and we ended up with this.
After bracing the corners, we then positioned the raised bed and filled it with multi-purpose compost, and lots of sieved topsoil that we got from Freecycle - the picture looks like it's all about to topple, it's not, it is level I promise!
And the left overs made this... It is now on a flagstone and will have herbs growing in it eventually :-)