nats,
A
lot of ATCOs I know are Qualified Met Observers. [One guy went on a course as an ATCO [non NATS]
then went on a Met course as a NATS ATSA 
As you may or may not know, the Met was done by the MoD, hence the "switch" to ATC[ers]
At Manch, the Met Observer stayed "on site" [on the a/f] for quite a while until the ATSAs were "qualified"....[as SAMOS] met obs.
On "single manning", i.e. one ATSA at night, the ATSA is allowed a "Two hour responibity free break", so SAMOS goes "automatic" for two hours.
Also, [at Manch] we do not have any ATCOs currently valid/qualified on SAMOS.
As to "The training"
wot I got....was
A few hours in the Training Section....
8 hours OJTI [16 wx obs] with the Training Section
A "Test" with a Qualified Met/SAMOS examiner
That is how I got my SAMOS certificate. NOTE,
not a Met Observers Cert .
I was trained by ATSAs.......will I train an ATCO?????
watp,iktch