Karen, Cirl Bunting is now extinct in Somerset. I believe there have been no records since 2001. From your description, have you considered Yellowhammer? That doesn’t mean of course that Cirl Bunting could not occur in the county but any possible sighting would require a detailed description and, if possible, photos.

Just wondering if anyone sees Cirl Bunting in Somerset?
Whilst I was away on 29th December my parents saw one feeding on the ground underneath the seed feeder in my garden. A male single bird until a robin chased it away. They did not get a photo and I have not seen it since but they are sure it was a Cirl because of the yellow strips. I do get reed buntings in and have a female visiting today. I will keep looking with the camera ready.