Mine failed on the mirror mounts, I had to put rubber U trim arround the metal plate on the stalk before putting the mirror on to pass.
Handbrake performance is allways an issue......
I was also told about the seatbelts too, butargued that they were inside the car not outside and got that through...
Speedo should have passed... They can't test it if it is on the front, so they will want to see the manual (check its "E" complicance)
If you fix what he failed you would be better of having the same person again, if you get a diffrent tester, although they are not suposed to check anything that is not on teh failed list they may find fault elsewhere....
I'm sure you will be able to resove... when is the retest?
good luck
Simon