[Simon1955]

Could i Rotovate now before erecting a Polytunnel?And how long would i have to wait before putting it up,The allotment is quite sandy and drains very quickly,A month ago i double dug it and put in about 4 ton of well rotted cow manure.

[Goldfinger]

I wouldn't. You still have to erect to tunnel + cover, therefore you'll be walking all over the beds etc.

If you've double dug in manure, if possible, could you put some boards down to walk on?

Then all you have to do is give the surface a wee forking over.

If you try and rotorvate once the cover's on, you may hit a stone / lose control and end up you and / or the rotorvator handles etc taking a flying lesson through the cover! 

[Simon1955]

Thanks Goldfinger for the reply,
I,m keen to get the P.T up,Although the ground has been double dug its still quite fluffy and is quite easy digging,i suppose getting hold of some scafolding boards would be a good idea if i can locally source some.