Notes
The Roll of Honour includes an appendix headed "Men thought to be from Peterborough who were killed in action, but about whom little can be discovered regarding addresses, regiments, dates of death etc". That page includes this entry for "H.E. Covell", whose rank it lists as Lance Sergeant, with no further details re address, unit etc. [The entry derives from a similar one on the original 1921 version of the Roll of Honour, which included the name Lance Sergeant H E Covell, with no further details].
(CWGC has no record of any H E Covell (or Cowell) in its casualty registers, nor do they record any Lance Sergeant Covell (or Cowell). None of the casualties named Covell (or Cowell) in their registers has a recorded address in Peterborough.
It therefore appears that either H E Covell served and died under a different surname, or he was mistakenly included on the Roll of Honour).