First of all, don't break it - that sort of thing's just crass. 
 
Anyway, this is quite interesting. I'm not 100% sure what this bass was originally, but it's been a decent-quality early 70s (1971/2) LP bass copy, very probably from the Fujigen Gakki factory. If so it would most likely have been an Ibanez, an Antoria or a CSL, since these all came from that factory. This is what it would have looked like:
http://www.ibanez.ru/info/catalog/1971/17.jpg
As you correctly say, it's been modified - it would originally have had 2 humbuckers in the usual positions and no scratchplate. Judging from the angled P pickup, it has been routed underneath the plate to take the pickup.
It's been stripped & refinished. I've only ever seen MIJ LP basses in black, and the butcher-block body construction of this bass was clearly intended to be hidden by paint. You can see black paint around the lip of the control cavity which is left over from the original finish.
It would be strange to paint over a flamed/bookmatched top like that - so I'm wondering if it's been veneered - although that would be an odd & costly thing to do to a bass of this type, and the scratchplate/pickup is certainly not a professional modofication.
I don't think the bridge is original, but I can't see any fitting holes for the original one. That might bear out the idea that the top's been replaced, or perhaps they're just hidden under the current one.
I doubt if the "Beeva" flyer offers much of a clue - judging from the lads' clothes that pic's from the mid 70s at the latest, and unless they were big enough locally for anyone to have talked about them on a local music history website, there's little chance of finding anything out. Besides, it's anyone's guess where "local" was - you found the bass in Manchester, their agent was in Wolverhampton & their management in Liverpool!
Very interesting old bass anyway - these are decent-quality instruments and I'd say worth looking after even though it's not in original condition - it's a 40-year-old bit of history and there aren't many of them around any more.
Jon.