G'day Philip
> this decided to follow me home recently, for a reasonable price:
>
> https://goo.gl/photos/VSLHHHP7s9kNbCPU6
>
> Anyone know the maker and possible date? Google obligingly finds me 
> similar items, but there seems to be significant disagreement as to 
> the manufacturer - perhaps a lot of people made very similar looking 
> tools?

If it isn't marked then it may also be a Preston.  Lots of UK 
manufacturers apparently "copied" each other but at the same time there 
were makers who specialised in particular items and supplied them to 
other companies who stamped them as their own and sold them on.  This 
was efficient, but required  faith on the part of the re-seller in the 
primary supplier if the re-seller was going to claim, stamp,  and sell 
them on as their own.

As an example, I have my doubts that Edw. Preston and Sons made their 
own edge tools.  Rules, plane bodies, cast iron items for sure, but 
Birmingham was a long way from the heart and acme of steel edge tool 
production in Sheffield (Gilpin at Cannock Chase being the exception to 
the rule).   Your gauge may be one of these tools sent out to be marked 
by others.  Or it may be an example that went through the factory the 
day the man with the stamp was off sick.

Cheers,

Tony B