London Info are only FISO's and hence couldn't identify traffic even if they had access to radar.
I'm talking about FIS aircraft which are identified and to which, workload permitting, I pass proximity hazard warnings on other traffic observed on radar. This is often generic eg 'multiple contacts operating near 'XYZ' VOR or 'traffic reported to be aerobatting near ABC'. This is to fulfil 'duty of care' without the pilot thinking he/she is getting RIS.
I'm sure you'll agree this does not absolve the pilot of the responsibility for keeping a lookout.