H C5507 - frame built in early 1991
...and this is all the information
At that time there was an obsessive watch for "technical markings", if it was an SLX it would be marked X, if it was a Corsa it would appear C
Lack of markings suggests either Reynolds 753 or a custom built frame (e.g. for profi team) - there are worse alternatives
If you want to get to the next information you have to disassemble the bike:
- check how the ends of the tubes visible through the BB cover look like (photo)
- what the inside of the steering tube looks like (photo)
- what are the markings on the steering tube, especially the card (if it survived)...(photos)
Nice colour btw.