We reported incidents of HAVS found with staff, some of whom had worked in industry for years, however because we had a system to find it, they were our RIDDORS, (and all HAVS ones are manditory investigation).
In dealing with tenders we found having ISO 18001 and the getting the SSIP add-on meant that the CHAS and tender reporting went to sending off a copy of the SSIP certificate and then the section was done.
Yes RIDDORS affect tenders, and perception of safety of an organsation, but with some supplemental information a Resaonable person can see the differences (if they want to), and yes you can decide there wasn't an issue, however as stated the person was walking between two buildings for an interview, the blame side of things doesn't really matter (other than who pays the bill), but an issue did occur, and time was lost.
A look at workplace transport HSG 136, and Management of Health and safety at work (L-21) suggests that movement around sites needs to be considered, and as there is no mention of roads/public footpaths in the post, the suggestion would be the site is enclosed (and so responsible), in addition to the landlord's responsibility as detailed according to lease, there was mention of getting security to do it, which seems very sensible. as such, there has been acknowledgement that action needed to be taken, and a sensible solution has been found, however the trigger for the change seems to be the event.
there was outcries years ago when people said if i half scrape the path then it's not as good as leaving alone (and abdicating responsibility), and I seem to remember statements from the hse at the time, however it seems that the person is on a walkway, and there is acceptance it is a route used for getting between buildings.
The responsibility then goes to providing a safe workplace - hse view driving as part of work (i.e. travel worthy of workplace status now), and it is a priority area for them, walking should be no different
I am aware that Transport for London talk about risk assessments for journeys between offices as part of their FORS courses, don't know your view, but whilst walking on a site a slip trip fall would be reportable. the consequences for some may be hip replacement again or similar, or broken teeth with ongoing care, however I don't see how/where the duty of care to the employee has ended.
In any case, it may well be a liability issue/discussion for insurers between the company and the landlord, but I would be inclined to suggest it would end with where the red line on the plans or fence is around the site on the site plan.
It is likely to be a claim in the future, but at least get it dealt with through the proper channels and notify insurers as soon as possible in case they try to refute the claim/liability back to the organisation for non-notification to them/following Insurers' proper procedures, could even ask broker.
If you percieve it's going to have a costly outcome, then at least you can get your evidence together (on grounds of compiling report/investigation to see if it is or is not a riddor, and if need be you could even ask at an IOSH local event a straw poll of would others report and what are the aggrevating or mitigating factors.
If you are in the position of having a friendly face at the local HSE office, you could ask, don't think it would result in an improvement notice or letter for gritting the floor under FFI, but it would be a potential risk.
Ask the MD as to weigh up the options either way, and then you have a decision with both options from the organisation, record what it is in a letter and then file with company secretary, at least there is an audit trail and the relevant info is all there in case anyone in the future comes knocking.
It's a suggestion, don't have to do it, but i think it is an answer to the problem whichever way your company (and you) can decide to go with.