In 1931 Smiths, then called S Smith and Sons (motor accessories) Ltd., decided to enter the domestic clock market and formed a new company, Smiths English Clocks Ltd., as the Clock and Watch division of S Smith & Sons (Motor Accessories) Ltd. with Cricklewood as the main factory.
Smiths were one of the first companies to produce synchronous electric clocks. These were put on the market towards the end of 1931. It seems that Smiths formed a subsidiary company called "Synchronous Electric Clocks Ltd" to produce these clocks as the first models are so marked.
In 1932 Smiths purchased a company called "English Clock and Watch Manufacturers Ltd" of Coventry and thus acquired the famous trade names Astral and Empire which they subsequently used extensively. Smiths were one of the first to produce a synchronous alarm clock, shown in advertisements in 1934, which they named the "Callboy"
The Smith's Sectric Mantle Clock, 1950's is valued at 100.00-110.00 GBP
If you plan on selling. There are some great sites you can sell from.
Facebook Marketplace is how most people post things for sale locally.
Etsy is a great site.
There is also craigslist locally which is free. Ebay is a great option. It does reach a lot of people, but items tend to sell a little lower on there If you do decide to try Ebay, I recommend setting reserves.