In reply to Adrian Nelhams:
That is a pretty old bolt design, the current Petzl Colinox has raised keying ridges rather than troughs, so it's likely that this was placed some time ago.
In the photo, I don't see any resin residue left in the troughs, so it looks as though the glue never filled these in and keyed the bolt in properly. Either the glue didn't mix and set properly, or it was placed at too low a temperature and the glue wasn't viscous enough to flow into the troughs. Modern bolts have more tolerance but it goes to show that sport climbing isn't "safe" and that you still need to take care.
I've emailed a link to this thread to a contact at the Yorkshire Bolt Fund, in the meantime probably best to avoid routes in the vicinity with similar bolts.