This car is similar to early Mk3 ( 850 / 1000 ) found here in Portugal... except for the front indicators and heater. Our early Mk3 had plastic heaters.
regarding the date build, our cars had toggle switches till end of 1970 , and the two boot badge combination ( Morris + 850 ) lasted till beginning of 1972... where this single badge type was introduced:
and the Assembly Plant... don't you have a letter after the body number ? like 'XA2S228609 S' ? Mk3 cars built in Portugal and Spain have 1 or 2 letters after the Body number to identify the Assembly Plant ( 'S' for Portugal 'ZA' Spain ) .
Regards
Luis