Interesting one stevef as I believe that B1.2 now has the privileges of B3.
I have B1.2 which also evolved from a BCAR licence. I only had electrical restrictions over 5700kg as electrics for light aircraft was always in the syllabus going back to 1978.
https://www.easa.europa.eu/the-agency/faqs/part-66
QUESTION
"I am the holder of a B1.2 licence (i.e “aeroplane piston”). Can I exercise my privileges for piston-engine non-pressurised aeroplanes1 of 2000 kg MTOM and below (i.e. category B3)?"
ANSWER
"By default, a category B3 licence is included in a category B1.2 licence because the basic knowledge requirements (66.A.25(a)) and the basic experience requirement (66.A.30) for a B3 licence are covered by the similar requirements of a B1.2 licence.
Provided that the qualification requirements are fulfilled, the B1.2 licence holder can release maintenance tasks performed on piston-engine non-pressurised aeroplanes of 2000 kg MTOM and below.
In particular the B1.2 licence holder would have to meet 66.A.20(b), which means that:
the applicable requirements of Part-M and/or Part-145 will be complied; and
in the preceding two-year period he/she has 6 months of maintenance experience in accordance with the privileges granted by the aircraft maintenance licence or; met the provision for the issue of the appropriate privileges; and
he/she has the adequate competence to certify maintenance on the corresponding aircraft; and
he/she is able to read, write and communicate to an understandable level in the language(s) in which the technical documentation and procedures necessary to support the issue of the certificate of release to service are written.
AMC 66.A.20(b) and GM 66.A.20(b) gives further explanations on the 6-months maintenance experience in the last 2 years, including demonstration of experience on at least one aircraft type per aircraft structure (metal, composite or wood)."
The worst thing about the modern licensing system is that the days of being able to speak to someone and get a rational decision are long gone. The tick box culture that pervades the CAA has made life for pre EASA licensed engineers a total misery. People are being asked to supply proof that doesn't exist largely because companies and records are gone and there was no requirement for an individual to keep such information.