Having had a white horse for 15 years there was just no question.
I pulled it out and saw on the back hints of another pony peeking out below the reinforcing boards. 15 minutes later I was home with tools in hand prying up rusty nails and boards singing, "Wild Fire" (OK- not really but go with it)
This white horse gets it's "paint" look from an old varnish that is amber and crackly...I rather like it.
I have no official information about the sign (other than I officially like it).
A search on the interwebs found that "The White Horse" was a pub situated in E. London and established in 1780. The pub closed in 1969 but had belonged to the Colchester Brewing Company passing to IND Coope in the 1930s.
I'm getting thirsty....