Hello Jason,
Re your look-up request, I don’t think Mansfield Library may be your best bet?
the reason I say this is because Charles Plumbe lived most of his life in Sutton in Ashfield.
He can be found on the 1841, 1851, 1861, 1881, 1891 in Sutton in Ashfield, the exception being the 1871 census where he is in Mansfield, and as you say is Postmaster, his wife Elizabeth (nee Alvey) is still living in Sutton in Ashfield.
The first postmaster in Sutton in Ashfield was Charles Plumbe appointed 1837 until 1863,
maybe that is why he is found on the 1871 census in Mansfield? He is with two of his unmarried daughters, with what I think says “Certificated Telegraphist” as their occupation, perhaps someone might have a look for you to see what they think it says? 1871 RG10/3474/37
On the 1891 census he is aged 77, a retired printer and for the first time stating on a census that he is Registrar of Births and Deaths, he was appointed in March 1848 until April 1897.
He was the first to publish a Newspaper in Sutton in Ashfield called the “Sherwood Gatherer” in 1844 which was superseded by the “Midland Gazette” in 1846.
I already had some directory pages which mention Charles Plumbe which you are welcome to, but can also be found here
http://www.historicaldirectories.org I think Sutton in Ashfield library is being refurbished so might be closed for a couple of weeks but if I pass any time soon I will ask if they have anything useful.
Good Luck
Sheila.