Hi guys, just after a bit of advice really, took a 130 mile round trip to Thorpe Park and back yesterday and noticed the car performing strangely on boost on the way up. First of all it normally hits 1.5 bar boost reading on my boost gauge but it was only hitting just over 1.0 bar for some of the journey up. Then around half way up there it starting hitting 1.5 again. Then I noticed the dump valve making a different atmospheric noise than usual and it didn't feel quite as strong and progressive when hitting boost. I've checked the valve today which is a genuine HKS SSQV and it seems like a plastic or rubber O ring has come apart inside. So my questions are A) can these be repaired? B) would this be the cause of the boosting issues? And C) would a standard DV go straight back on or would this cause me any issues?

Thanks in advance.