Well, if mail went on Sunday, it seems reasonable to expect that the express would too.
As I understand it, mail was not delivered at all in the country (I'm at Longbourn here) but kept at the local post office. A servant would be sent to collect the letters and have them on the breakfast table by that time, which I believe was generally around ten. Expresses, however, clearly delivered directly to private houses, since in P&P the express comes directly to Longbourn after they are all gone to bed, an hour at which no servant would be sent to fetch it.
By that logic, it seems reasonable to suppose that an express would probably ride on Sunday and deliver on Sunday. I shall amend accordingly, and thanks for the help!
As I understand it, mail was not delivered at all in the country (I'm at Longbourn here) but kept at the local post office. A servant would be sent to collect the letters and have them on the breakfast table by that time, which I believe was generally around ten. Expresses, however, clearly delivered directly to private houses, since in P&P the express comes directly to Longbourn after they are all gone to bed, an hour at which no servant would be sent to fetch it.
By that logic, it seems reasonable to suppose that an express would probably ride on Sunday and deliver on Sunday. I shall amend accordingly, and thanks for the help!