How do you go about finding a taxi/car to go to a site near Worcester or Bristol and arrange the return? Would the hotel help? or should we just find a taxi stand.
Have you checked the National Trust website for the property or properties you are visiting? They have travel information. Otherwise, I'd use a map and the Yellow Pages website or Google maps to find taxi operators close to where you are starting from. Arrange the return with the driver.
Are you staying nearby? If not, then maybe hiring a car and driver for the day would be a less expensive way to go. I would hope your hotel would be able to help.
The properties are outside of BristolDyrham Park, and outside of Worcester. I've booked a taxi from Worcester, but for Bristol there was only one response for about 63 pounds one way. I'm planning on contacting taxis after we arrive in Bristol and trust there will be a less expensive option available.
You could try sending an email to Visit Bristol tourist information office and see if they have any suggestions.
Dyrham Park is 8 miles from Bath - might be cheaper to go via there. The taxi fare is high because you are effectively paying for the round trip.