Or you could try "Zed Shed" featured here:- https://z4-forum.com/forum/viewtopic.php?f=4&t=129554
The proprietor, Mike, has created some debate on this forum due to poor business practices, but he definitely seems to know his way round Z4s. If you just want a job done before you pay it might save you some miles.
In 2016 he replaced my rear brake pipes and cut and coded a flip-style key for me for less than £200!