Hi. No, it's not an antique, unfortunately.
I've yet to see a clear definition of the terms vintage, veteran and antique in relation to bicycles. From what little I've seen, I'd classify 'antique' as any bike/trike that is about 100 years old, or more.
Prices for antique bikes are through the roof, esp. in Europe and North America. I can't afford to collect antique bikes :-( but I keep a lookout for anything old or unusual. Picked up a 1948 BSA 3 speed for A$10, and that is the oldest machine I have which is mobile. Also a late 70's / early 80's Malvern Star 12 speed derailleur with the early (?) 6 cog freehub, A$10 as well. Nice bike, this one, but it has a weird bottom bracket. Bit of a headache, too. I rebuilt it with a 3 speed hub, so that with the lamp on the front fork and a dynamo on the seat stay bracket, it looks like one of those "Clubman" bikes which used to be common in the U.K.
Getting back to the Claud Butler machine, the owner's wife says it's a 1951 model, but a cycle collector/historian whom I rang puts is roughly as a late 50's - early sixties, judging by the level of equipment. It's just a basic model, a clubman type. The five speed basic Campagnolo gear will be O.K. on the rail trails - no hills, just gentle gradients. I may never get the chance to grab a Claud Butler bike, so I'm not passing this one up. The Brooks saddle I can swap over occasionally to the 1940 Malvern (3) Star, when it is finished, maybe next year.
Regret that I don't have a scanner. Any spare cash goes on bike parts.
Here's a good link for old bikes:
http://www.classicrendezvous.com/British/British.htm
Cheers

and Thanks.