I have an area about 3m wide by 10m long - with really heavy soil. Am going to slab it all and have raised beds. Is there anything I can do to improve the soil (being that there is loads of it!) - or just ditch it and use loads of compost?
If it's heavy clay I wouldn't bother with sand. I'd just go for well rotted manure, compost and leafmould to improve the structure.
Once you've made the beds up them you can just top dress with manure / compost as neccessary - which is wha you would do with any kind of soil. The bulk of the work would be done when you make the beds.
If you haven't had a better reply, I'll get back to you tomorrow - have to take colic-monster to bed now.