I googled Royal Winton and they have a picture of a set that looks like yours. It is named Marguerite.
In 1928 'Marguerite' the first Royal Winton Chintz pattern was launched and was an immediate success. These tightly grouped, highly detailed and vibrant all over floral patterns were to become a milestone in the company's reputation for versatility and beauty. Following an advertisement in the 'Potteries gazette' in 1929, Royal Winton became the established trade name for Grimwades Limited and has remained so through to the present day.
I think I would remove the tape from the top of the pot as it may damage it.
I tried Replacements, Ltd and they show your teapot in stock with blue trim and refer to it as Countess shaped. They have it in the blue trim for $599.95. They list a few other teapots in assorted shapes in that same price range. They also list various pieces in that pattern with gold trim, which I think is what you have. They do not have any teapots in your style in stock, so thus no price. However, they do list as available some of the other styles, and they seem to run about $50 more than the ones with the blue trim.
Don't know how long Doug's grandma had it, at least ten years that I know of. She used to bid on storage sheds, and kept EVERYTHING!!!!! Out of all the stuff, this is the only thing that was really worth anything ^_^
Oh, I love watching the shows where people bid on storage units. If I had some money to spend I'd love to do that. I have some jewel tea dishes, I started collecting them years ago. My mom had a few pieces left of her set (we are talking about the 30's) so I have been adding to it with help from family and friends. One day I would like to set a table with a couple place settings on a jewel tea tablecloth and take some pictures. I've been saying that for several years now so don't know when that will happen.
My son in law went to one. He said it gets crazy!!! Him and his dad have been going to a lot of yard sales, he found a wine bottle that was made in Germany when they held the World Cup for soccer. Bottle had $9 tag on it, picked it up asked lady what she wanted for it...he got it for .50, lol.