Thanks for the responses. I bought the kit from JJC race and rally as I ordered from Frost and they canceled my order saying that they did not have any stock.
The tank was brand new as I am converting the car to an in tank fuel pump. I Wanted a fit and forget solution which this product has certainly not supplied. I followed the instructions to the letter and spent many hours cleaning to be on the safe side. I doubt the tank could be damp as after drying with a heat gun and leaving overnight it was then in the sunshine for 3 hours. It was more than 50 degrees C before I moved it to the shade. The bubbles are like little blisters. I tried cutting open the one in the lid and it is completely hollow with no covering on the lid.
I have a feeling that the kit may have been an old one as it set far too quickly, either that or the humidity in Basingstoke yesterday was far too high.
It does look like gas trapped in the bubbles.
