The 8KB "extra" memory, was in fact a single 4164 DRAM chip (64Kx1bit).
Because there was no space for a new chip, Amstrad designers took off one of the ROM chips, and put it in a daughter board, along with the 4164 chip. Wires connected pins at the ROM from the daughter board to the corresponding pins on the main board. The wires were hard enough to make difficult to turn the daughter board over and reveal the trick: no wires were connected from the DRAM chip to the main board. Even the supply pins were not connected!!
While based on the CPC 464, at least some of the 472s got the ROM v2 with Locomotive BASIC 1.1, which normally was built into the CPC 664.
After the rule changed there was also a CPC 472 with spanish keys and BASIC 1.0 available for a very short time.
The CPC 472 with spanish or british keyboard is very very rare.In some interviews, Amstrad developers stated that they have never heard of the CPC472, so it's possible that the daughterboard was made by Indescompt (the spanish distributor), not by Amstrad.