Hi all
thanks for all the advice & tips
it's a runner
in addition to the other bits we decided to replace the in tank pump as it was snotted up badly & we couldn't get it clean,
merry xmas if you like that sort of thing & bah humbug if you don't.

thanks Steve

Ps. i'll try & scope the can later before it goes if i get time as i'm curious why it looked like that.