Hi Colleen and
to the forum.
I know Cheltenham very well, as I studied there and have family who live there.
The vet you need is not too far away in Swindon....the practice is called Great Western Exotics, and they are based in the Vet's Now building. It's a straight forward journey from Cheltenham. The practice was set up by one of the most highly regarding Avian vet's in the U.K. Neil Forbes, he retired earlier this year, but the four specialists there have all trained and worked closely with him.
The practice is now headed up by Tom Dutton.
http://www.gwexotics.com/
Also there is an excellent professional parrot boarding establishment in Cheltenham, which I can personally recommend too:
http://www.theparrotlodge.co.uk/
The ladies there have experience with all breeds of parrots, use Great Western Exotics, and have excellent bio-security processes, so you can be assured that your birds would be well cared for.