Dave,
Of the top of my head, I think CL range of numbers is around 1958-60, but cannot find proof yet. The chassis number looks reasonably early (ie 1950's).
Two suggestions, first, John Pearson, who comes on this forum, had or has a RL recovery and using his numbers it could give an indication of age.
Secondly, there are two Yahoo forums covering Bedfords and the one I look at is Bedford vehicles (I think) with a lot of knowledgable people on there regarding dates and serial numbers. The other forum is something like Rsoles, which is apparantly dedicated to RL trucks!
Hope this may help.
Richard