Im gonna imagine that Cogsworth has been living in the same neighborhood in England with my Beauty And The Beast OC Thomas from the time he was born until he was 18 years old and throughout those 18 years he and Cogsworth has been really good friends or maybe even best friends and spend alot of time together hanging out with eachother and Cogsworth probably teaching him many subjects he knows and how to get things done.
And some time afterwards Cogsworth got the job at being the head servant in the Prince's castle in France and the last 2 years his friend Thomas has gotten a bit depressed not having Cogsworth around to spend time with anymore, and so his parents decided to let him ride with a couple of other guys in a small ship and sail the seas for several weeks to cheer him up which it did since one of his dreams is to explore that is until a bad storm came after sailing for a few weeks and the ship went out of control and ended up crashing in South Africa near a jungle where abunch of wild animals lived and the ship ended up killing the 2 guys who were with him and he survived, and since then he had been trapped there and he decided to toughen up and taught himself to be skillful at defending himself if he wanted to survive there, and over 10 years went by and no one showed up to rescue him so he ended up figuring out how to rebuild the ship that crashed on his own since he was already good at making model ships and other model things, so after years he managed to rebuild the ship and he sailed off from South Africa where he had been stuck in for the past 16 years.
And the first place he thought of going to is to the castle where his old friend Cogsworth was staying at since he spend most of his life in England by his side and he was the very first person he thought of seeing after all those years and thats how he and Cogsworth reunited.
I also love imaging him teaching the Prince his skills he taught himself while surviving in the South African wilderness and jungle so the Prince can be good at fighting and maybe even defend himself from possible intruders or threats to his castle.
Also like I mentioned in a previous Journal Entry I imagine him going through a major personality change from when he was living in England and from when he was living in South Africa, while in England he was soft spoken quiet and a bit shy though he was more open towards Cogsworth, and after spending those 16 years in Africa toughing himself up he became much more assertive outgoing rambuctious and very adventurous which surprises but yet impresses Cogsworth.
:EDIT: My BATB OC Thomas is 36 years old.