the best way to seal poly is with chloroform...unfortunately you will not be able to buy it without being suspected of wanting to knock someone out :) Use a small dab of clear silicone, leave for a few minutes then flatten the blob with a wet finger (water or spit) wipe the excess off your finger with a piece of tissue
bob
March 2010
I can answer this question...
how to repair small hole in polycarbonate conservatory roof?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix roofing.