I've just heard that Yeovil Railway Centre is hosting its first ever Steampunk day on Sunday the 20th August.
I don't have any other details yet, but I believe there will be traders and the plan is to make it an annual event.
Yeovil Junction Station
Stoford
YEOVIL
BA22 9UU
http://www.yeovilrailway.freeservers.com/ (http://www.yeovilrailway.freeservers.com/)
Sounds good. I'll try and make it.
I think you are half a year too late.
Sorontar