No.4 with unusual serial number

There's a guy selling a very nice looking No.4, I assume English, that went through the FTR process. The receiver and bolt both bear the seral "X0026". The pics I've seen so far shows a pretty nice rifle, walnut stocked, brass butt plate and micrometer rear sight. I've never encountered a serial number like that though. Any input would be appreciated.

It could be a 1942 BSA No. 4, pictures will be a big help

"found" the rifle you were looking at, it is a 1942 BSA (B under the safety) that went through FTR at ROF Fazakerley