Dumping fuel from tank breather...fix needed.

[kartman24]

On my newly rebuilt car i have been told i am losing fuel on roundabouts when the tank is quite full, the tank is baffled but the breather is on the left hand side of the tank, i am doing a track day next week so need to find a fix. I have taken the breather pipe up about a foot and kinked the top of it with a cable tie as it loops back down and out under the car but that has not helped. I am looking at the various fuel valves but can`t get a definitive answer from any of the suppliers that it would work in the way i need it, i.e air in but no fuel out. I think that maybe a roll over valve might work but would there be a possibility of fuel getting the wrong side of the moving `ball` and thus stopping the air getting in? Anyone solved this issue and if so how did you do it? I don`t want to have to replace the whole tank, there must be a simpler way. This is the valve i am now looking at, thought appreciated.
https://www.ebay.co.uk/itm/174205079...Bk9SR5CdyJWpYg