Criminal

I've asked a few questions on my common assault charge involving my ex girlfriend recently but I haven't yet mentioned the involvement of a certain Police constable. I didn't know the investigating officer at the time of interwiew but found out afterwards he was the former partner of friend of mine (ex from years ago). They had recently split up due to constant rows and he had been cautioned for sending her offensive texts and sexual picture messages and recordings of him having sex with his new girlfriend and also violent behaviour. This had caused her to have a breakdown. The P.C was very jealous of me; I've found out that my name was brought up in a lot of arguments so I was mentioned in the prosecution against him. He kept his job by the skin of his teeth and my friend was assured he would never be allowed to work on cases of domestic violence. In my case the victim has lied about and exaggerated many facts. Recently she came to my house ( i reported bail breach)and told me she and the P.C had talked about my involvement with his ex and he asked her how badly she wanted to ruin me and basically tainted her statement. He asked for emails I'd sent her from work to try to get me sacked.He told my solicitor I would be bailed in 10 minutes and the cps would make a decision the next day,but locked me up for a further 4 hours when solicitor left the station and charged me. He failed to interview the only independant witness which would have seen me get a slapped wrist or a caution rather than being £2k down on solicitors.I am 40 and have no previous dealings with the police.
Would police professional standards allow him to work on my case?
Should he have told his superiors of the situation? Should my solicitor be using this as part of my defence as he seems reluctant to do so?