Just wrote a massive reply... and lost it, I'm very hacked off!!
Anyway I looked around, I am in same position as you. Screwfix is V. expensive but says it lasts.
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=10103&cm_re=SEARCHPROMO-_-WEED%20FABRIC-_-10103&ts=74219I found
http://cgi.ebay.co.uk/2-25mx11m-WEED-CONTROL-LANDSCAPE-FABRIC-100-GSM-PRO_W0QQitemZ290153395395QQihZ019QQcategoryZ75584QQssPageNameZWDVWQQrdZ1QQcmdZViewItemIt is the same weight 100g/sm and Loads cheaper. dunno about rot proof though. I didn't pay postage as my in laws live in Boston so they collected for me.
I got it back and have laid it on the paths I have spent all year weeding, getting very frustrated. I have used double thickness as the weave isn't as tight as I'd like (or that I have in a piece of fabric given to me by the steward and she doesn't know what that is!) so I have used double thickness and then put woodchip over them.
on the half the plot I have covered in underlay etc. which was breaking down I have replaced with laying cardboard to encourage seeds to rot and worms to dig and cast for me! and covered the card with the fabric. this land will be used in the next year or 2.
I feel much more on top of things and more positive about next year. but we'll see. I am shocked to hear people experiencing the fabric breaking down after a year Yikes :shock:
Previously with the underlay I used the wilkso stuff which is such a waste of time, no ood at all, untill we lay card under it to stop the light, even the where the foxes walked it was torn up.... rubbish!!!
anyway welcome, and let us know what you do!