Ok, no offence intended, I was commenting on the way it sounded to me, the PO should never have really accepted the oversize articles in the first place.  I get what you're saying, but at the end of the day, better if everyone is honest 

All that aside, I post most days at the same PO, sure, I don't spend as much as you, but just the same am treated as a valued regular customer and as stated previously, 99% of my mail is large letter, and if it's even a fraction too tight for the slot (it is supposed to drop through with no force applied), then they knock it back.  There are some here who disagree, but the staff have told me, if it doesn't fit through the slot it is likely to be damaged by the machine/equipment (and the last thing I want is customers receiving damaged goods).

As I said bottom line is I confirmed with my PO yesterday and they are adamant, not all large letters are now considered parcels - only the oversize ones as has always been the case.  I would be checking again with your PO or changing PO's if that is possible

(and I wouldn't be tempting fate )