Please help me identify this possibly classic frame

[ForestHill]

I only have a couple of things to go on with identifying this frame.
There are NO details of frame manufacturer, I'm hoping someone might be able to put it together from these clues though.

This serial number on the BB

Columbus dropouts

And these 'heart' lugs

And here's the whole thing

Notice braze ons for mudguards and panniers, and the option of using caliper or canti brakes (drilled and braze ons). All of these point towards cyclocross/tourer but I have no idea what it is.
Not knowing isn't a massive problem, I'd just rather know.
When I got it it had really nice components so this makes me think it is something sweet under that nasty (hand) paint job.

Thanks.

 

[Old Ned]

Unless someone can make anything from the serial number I reckon it will be vary hard to make a definite builder for it. The lugs are standard Prugnat or similar and, with the Columbus ends and drilling under the BB for a plastic cable guide to be fitted, makes me think around mid 80's-ish?

Lots of builders at that time made virtually identical frames.

 

[ForestHill]

Unless someone can make anything from the serial number I reckon it will be vary hard to make a definite builder for it. The lugs are standard Prugnat or similar and, with the Columbus ends and drilling under the BB for a plastic cable guide to be fitted, makes me think around mid 80's-ish?

Lots of builders at that time made virtually identical frames.

Yep, you're probably right. From the large serial number all I can think is that it must be a well known manufacturer, unless it works in a different way.
It looks a lot like a Holdsworth serial, I just wish there was a database of the numbers like with some others.
Thanks.

 

[hamster]

I'd go with early to mid 80's. The lack of a braze-on for the rear brake cable would suggest the earlier end of the 80's.

 

[ForestHill]

I'd go with early to mid 80's. The lack of a braze-on for the rear brake cable would suggest the earlier end of the 80's.

Oh forgot to add, it's got this internal routing for rear brake - goes from front right to back left.