Why are some MPs referred to in the Order Paper with an honorific, while the majority are not?
For example, in the Order Paper for Wednesday 6th June 2018, the MPs asking questions of the Prime Minister are listed as
Q1 Alex Chalk (Cheltenham)
Q2 Eddie Hughes (Walsall North)
Q3 Mr Steve Reed (Croydon North)
Q4 Jim Shannon (Strangford)
Q5 Melanie Onn (Great Grimsby)
Q6 Chris Skidmore (Kingswood)
Q7 Lloyd Russell-Moyle (Brighton, Kemptown)
Q8 Bill Grant (Ayr, Carrick and Cumnock)
Q9 Martyn Day (Linlithgow and East Falkirk)
Q10 Mr Paul Sweeney (Glasgow North East)
(with the bold added by me, for emphasis).
I note that, elsewhere, these same MPs seem to be referred to in the same way: for example, Mr Steve Reed's Parliamentary profile versus that of Eddie Hughes.