mid boost my dump valve (recirc not atmospheric) is dumping so i have lack of power what can corse this it sounds like a massive boost leak but its defo coming from the d.v any ideas

faulty n249 valve as this controls the dv

Or the dump valve itself needs the spring rate tightening. If it's a Forge one (007 or Split-R) you can turn the top of it clockwise to tighten it. If you have it turned too far anticlockwise it will leak boost all the time.