If I had wanted that type of service, obviously I would have filed a flightplan.
Sorry this is a bit of a tangent, but the above is indicative of the chaotic UK VFR 'flightplan' issue. I guess that the reason that some PPR places might make an overdue report is that almosy no UK pilots file VFR flightplans unless going foreign.
IMHO the reason for this is that the plans don't go overdue by default as a rational person might expect, and as they do in the US: in the UK a 'responsible person' has to report you overdue. This might be a FISO if the airport is manned, but it's no-one if it is unnattended/out of hours etc.. In my experience not every VFR pilot knows that. (OK, I know you are supposed to appoint your own 'responsible person' for your 'do it yourself' VFR flightplan, but whose that going to be? Your wife/partner? "Don't worry dear, flying's perfectly safe really but I might crash in the sea today, so if I don't come home please call SAR!")
The effect is that there is little point in filing a VFR plan in many circumstances where you might need them most - flying late in the day, flying in weather where diversion might be needed and so on.
So it might be a good idea that some PPR operators will file you overdue. Problem is, as is said repeatedly on this thread, that the responses to PPR phone calls are so variable that it's hard to remember weather the operator was interested, noted your reg, etc.. or not. And by the time you phone to announce non-arrival after diverting somewhere else, they've all gone home anyway.
For a professional solution look no further than flight service in the US. Maybe some of the buckets of (our) Euro money under the common charging scheme could fund a proper VFR flight plan service through London Information. Then some of the PPR silliness could be replaced by 'flight plan required', as they are in Ireland (where you still need PPR!)