Rainbow Langdale-smith

Hi, I've just TUPEd into a new organisation and in doing so it has messed up my tax code on my second job which is very low paid, pushing it to the 40% rate when it was BR. Combined with my main job I am still under the 40% threshold so it is wrong, but I can't see how to correct this all on HMRC. I also should have WFH tax allowance due to the specifics of my main role but that's lost too. Is all so frustrating.