Deleted part because I misread. Too early in the morning
However… Recommended reading! It completely tallies with the enlistment records. Full story of his career! Wounds, current situation. How his wife is helping, and how she wouldn’t pawn his medals because he had gone through too much to earn them.
Wellington Journal
19 May 1900
Page 9
This explains why he was a coalminer in 1891.
In Fredericks own account.
Joined Royal Engineers in May 1878
Sent to Aldershot and on to Chatham.
Dec 1878 went to South Africa.
1881 returned to England.
1882 sent to Egypt.
1886 he was transferred to Reserves and completed 8 years in that service.
All fits in with the date you have of 1894.
The 1886 marriage certificate will give his occupation at that time and hopefully more details of his father.