Thanks everyone, really helpful.
The previous owner had started to put in some small drainage trenches, interestingly all the other owners have commented to say they don’t know what he was thinking, but it seems sensible to me!
It’s fairly flat with no grass, just sparse weeds at the moment so I’d be looking to cover quite a large area and like the sound of the free woodchip, I’ve asked the parish council who run the allotment to ask the council about free drops from landscaping as this seems to be done at other allotments within the wider area. I’m definitely liking your thoughts cleansweep, very multifunctional. Thanks