Last MKIII I rode on... R.I.P 
But WAIT... U sure SBS850P dereg oredi??? Coz juz now I passed
by HGDEP and STILL saw SBS847A still peacefully
sitting at the lay-up corner. Dereg?!?!
For 850P, not de-reg yet, but probably awaiting de-reg. Means they
probably didn't bothered to ask for a Lay-Up status since it is
going off anyway in like a few days, that's why OneMotoring didn't
show it as Laid-Up nor did anyone see it on the roads in the past
weeks.
As for 847A, the depots have the practice to keep some of their
supposedly de-reg Mk3s around for some time more for spares for the
remaining Mk3s before finally towing them out to scrapyard/export.
Common in BNDEP, could see the Darts 749A 870G still in BNDEP even
though they were officially dereg-ed like at least 3 months
earlier.