[redwine@roses]

I would be grateful for any advice on cladding a polytunnel, there seems to be about six different types,the poly will be for general use nothing specialist

[DD.]

Have a look down this.

Whatever you do the polythene MUST be UVI (Ultra Violet Inhibited), otherwise it will go brittle in a year or less.

http://www.allplaz.com/acatalog/Ultra_Violet_Inhibited_Polythene_Sheeting.html

[jameswburke]

Very good online step-by-step guide to building a polytunnel:

http://doorgarden.com/10/50-dollar-hoop-house-green-house

[mumofstig]

lots of polytunnel links and advice on the polytunnel sticky 
here