Is this a Rixon?

Were all Rixon frames numbered with a RX suffix?
I have one that has this and just bought another which doesn’t so, although it’s nicely built, it could be something else.
It looks to be an attempt to build to mid-Century style with 120mm spacing, highly recessed flutes on the chain stays, bolt-on brake fitting, flat fork crown.
There is no sign of a seam on the bracket shell and the threads are fairly deep. The seat bolt is recessed on one side for an allen bolt, the other side threaded.
Given that Rixon was a trading name and their builds were by Neil Shankland could this just be a refurb of a much old frame with a few modern touches added on. Others offer that service, did they?

Rixon is the shop brand of Rick Green Cycles in Handforth which used to be my LBS.
https://en-gb.facebook.com/RickGreenCycles/

Don't recall a serial number on mine, unless it was hidden under the paint.

A discussion here mentions serial numbers.
https://www.lfgss.com/conversations/261940/

Cheers, I saw that but it’s not conclusive. I will post some pictures of my mystery frame tomorrow.

Photos added

I have a Rixon from 1989, it doesn’t have any serial numbers under the b/b.
Mine now serves as my bike for Zwift miles.
You could contact Atlantic Boulevard as they built these bikes and helped me identify mine.

Cheers Salty