Do you have the birth cert for John as he is the only one born out of area to see if they are any clues to the name change?
We've decided to return to the Leigh / Packman saga and have bought Walter junior and John's birth certificates to try and trace their movements (already had Thomas') ..
~ 22 Mar 1877: Walter Robert Leigh born at Mount Street, Brecknock to Walter Robert Leigh, private 24th foot, and Mary Ann Leigh, formerly Thomas. Informant: W R Leigh, father, Barracks, Brecknock;
~ 28 Dec 1878: John Richard Packman born at Rhosfach, Blaenporth, Llandygwydd to Walter Robert Packman, coachman, and Mary Ann Packman, formerly Thomas. Informant Mary Ann Packman, mother;
~ 31 Dec 1880: Thomas Henry Leigh born at Mount Street, Brecknock to Walter Robert Leigh, groom (domestic) and Mary Ann Leigh, formerly Thomas. Informant: Mary Ann Leigh, mother, Mount Street.
So another twist of sorts in that Walter (child 1) and Thomas (child 3) were both born in Mount Street, Brecknock and registered as Leighs, while John (child 2) was born in Llandygwydd and registered as Packman.
Taking some leave in July or August so planning a trip to the library in Brecon or the records office in Llandrindod to see if they have anything to help. Someone looking for Walter Robert about 10 years said they had a photograph of him in army uniform from a newspaper
Tried contacting her a while ago but no reply