Armoured Dozer

[kevinT]

I have just found a great picture of "Slippery Sue" a Canadian Armoured dozer.
It is on British Pathe film ID 2145.01 frame 189 and on.
The AoS is 344 with an Army Group diagonal b/ left to t/ right.
According to "British Miltary Markings 1939-1945" that AoS should have the bar below. Is this another book error?
Can anyone make out the WD serial. I have last 4 numbers as 1007.

Cheers
Kevin