G'day exfarmer
That's a great story, and they have many years of life in them.

I think that Webb is a 12 inch - making it a Webb Wasp (6 blade reel?).
The handle design indicates this is a post-war design.
They sold here from about 1947. So c1940 or c1950s.
The handle design changed in the 1960s.

A Manual from the OLC here:
http://www.oldlawnmowerclub.co.uk/technical/opman/webb-wasp-whippet

Decal Here:
http://www.ebay.com.au/itm/Webb-Wasp-Vintage-Mower-Chain-Cover-Decal-/252911474466

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Jack