Hi Steve, to be honest I've never seen the point of raised beds, unless it's to alter the soil, eg, if you have alkaline soil, and you want to grow lime haters, or you have poor drainage etc, the only advantage is that you have something to rest a board across, while you plant out, but if you have narrower beds, and you can get to both sides that also solves the problem, Derek.

On the other hand of course you could pop pellets down the inside sides of the boards and get the slugs before they emerge!

I think people like them partly because you can cram more in, but with an allotment would you need to?

I can only see two reasons for having raised beds. One is for drainage (as has already been mentioned), the other is if you have difficulty bending and stooping.

Raised beds also allow the soil to warm up earlier as more of it is exposed to the sun. I would not say that raised bed borders harbour more slugs as the soil tends to be drier and therefore less attractive.

I have heavy clay soil and now have 7 raised beds 11" high which I have built up buying Growbags.
Realised last year that the damp soil would eventually rot the wood.
I have a big heap of strong unwanted plastic that came from a factory. Next job when it warms up is to move the soil away from the wooden surrounds to dry the wood, and then cut plastic to line the surrounds on the inside and protect it.
Then plant up the beds.
I noticed the Sunday morning BBC2 programme 'Beechgrove Garden' during the season had some very good crops from their raised beds. Must be because they are warmer.
Anyone in doubt could try with one, using scrap timber as they are too expensive professionally made.