It seems to be bit of a lottery.
And to make things worse, the lady in my local post office told me yesterday that the (large letter) item I posted last week should really have gone as a small parcel (it shouldn’t, being a £7 passport cover and well within the size limits) but it was okay because she smudged over the price on the postage label so it was illegible and no one would know!!!
So now I’ve got a parcel in transit to the US which has a tampered postage label on which I thought was probably not a legal thing for the post office to do!!!