Hello Muriel, and welcome to the GMB.
Your lighting bowl is indeed Jobling - a design that was first Registered on 3rd December 1946, and although you haven't attached a picture, there is a photograph in the Jobling book - it's a very attractive item.
Many of the Jobling designs are marked with the Rd. No., similar to yours. Do the mermaids and dolphins have an opalescent appearance (a transluscent milky look), or are they simply plain frosted glass?
I would imagine this is not a common piece - Jobling is collected, and we have people here who I hope will give you more information soon.
