boosey and hawkes

I've got a bass clarinet that I'm itching to know the year of manufacturing. I have a collection of Boosey and Hawkes serial numbers from their soprano clarinets, but nowhere on the internet can I find information on their bass clarinets and manufacturing years for them. Here's a little bit of...

I have just bought a Boosey & Hawkes Emperor clarinet in a charity shop. I got it serviced in a shop near where I live. I recognised the wood as African Blackwood before I bought it (I used to be a flute maker) and the shop claimed that the clarinet is also at least 63 years old with sterling...

I have dug out an old clarinet, which my dad says is at least 60 years old. It is a Boosey and Hawkes Regent, serial number 157841, but I can't find that number on any tables. Does anyone know, or can have a rough huess on its age?