Advice on Grant Vortex Mag-One filter unit service required

[ppeetteerr]

Hello all,
I have a Grant Vortex Mag-One filter which is leaking from one of the three caps on the top of the unit, I think its the central black one(see Photo attached)
I have some new o-rings ready and the service instructions (see attached Photo) but am not sure on a couple of items and hope you can clarify.
Can you advise me what these three caps are, I believe the central black one is the magnet, the brass one is the air valve and have no idea what the yellow one is (it has numbers written all around it). Can you please confirm if that is all correct?
Regards
ppeetteerr

 

[SJB060685]

Middle one is magnet, brass valve is bleed and the other wheel with numbers is set to the month of installation/service for future reference. Installed/serviced in June then set to 6. These units should be serviced yearly along with the boiler, in fact any decent engineer will be doing that at the time of boiler service as well.

 

[ShaunCorbs]

Tbh looks like it’s needs swapping as it has the same issues as the tf1

 

[exedon2]

That looks like one of earlier mag one
Current ones have chrome air valve
Would agree with Shaun change it for something better we use fernox omega.
Except on vortex blue boilers when you have to use mag one to get warranty.