PAL in ZX Spectrum +2 have name:

 HAL 10H8ACN  8634
 AMSTRAD 40061

Package:
 DIP 20
 
Manufactory sign:
 MMI

info: http://www.embeddedlinks.com/chipdir/c/m.htm

MMI
(Bought by AMD and later became part of Vantis)
Monolithic Memories Inc.

Poke2003.