@ Ladybirder Ermm, that's not quite what happened, nor exactly how it works, Ladybirder.
IPSA investigates claims of misuse of expenses and wrongdoing by MPs. They create a report based upon that investigation .That report is then passed to the a Commons Select Committee, in this case the Committee on Parliamentary Standards, a 13 strong cross-party committee which recently accepted lay ( or non MP) members. They will then discuss the recommendations within the report and either accept or amend accordingly. The lay members were introduced to the committee in recognition of the fact that the system was still MPs sitting in judgement on MPs, and this was their effort to dilute that, but the fact that those lay members did not get a vote undermined that. Those lay members can produce a dissenting "minority report" if they wish to.
But this system still means, essentially, that MPs are sitting in judgement of the actions of other MPs and is hence open to peer bias. I,along with many other people,thought that what we would be getting when IPSA was formed was a truly independent regulatory body. There is still a way to go before that happens, it would appear.