Loss of tyre pressure

[flakey]

have your tyre fitter remove the tyre, replace the valve, clean up any corrosion on the wheel and then refit the tyre using the bead seal black sealant (like liquid rubber), rebalance your wheel, your problems should be solved, shouldnt cost much at all maybe £10 piss easy job for a tyre fitter. even the likes of ATS or national tyres or bathwick might do it