Hi I have removed a damaged battery box from my Lunar and replaced with a new one. I have some sealing strip which has proved troublesome to apply. I am confused as to how it should be applied. Initially I had applied to the box but can’t get the straight mastic strip to go around the corners of the box, I tried cutting into strips and over laying the corners but then the box wouldn’t fit flush to the van as the mastic is too thick. I must be a bit dim as can’t really see how it is applied without gaps in the sealing strip - any advice greatly appreciated