Hi, I had a new boiler fitted a year ago and it's just come to light the feed and return are the wrong way round. I know there is no problem as the TVRs are bi-directional. I just want it right. I'm happy swopping over the pipes which are on the wall, but I have 2 pipes running side by side across the loft which I need to swop over but I can't think of a neat way to do it which won't cause on air lock. Any suggestions?