'Arthur' and Mabel were indeed divorced.
First, Arthur Carmichael Percy married Mabel Moore 14/12/1892 in Register Office, Derby - he is shown as 30, Elocutionist, son of Thomas Percy, Commercial Clerk - she aged 21, dau. of Henry Moore, Traveller. The marriage certificate is shown in the divorce papers.
1901 Census shows Mabel - after remarriage - as bc.1876 Nottingham, and there is indeed a birth for a Mabel Warhurst (the other name referred to earlier) in Dec.qtr.1875 Nottingham.
Divorce - petitioned 31/10/1899, Decree Nisi 29/1/1900, Final Decree 3/10/1900 and it was he who was the petitioner - Thomas Percy Carmichael otherwise Arthur Carmichael Percy v. Mabel Carmichael on the grounds of her adultery with Henry Gordon Smith (who she subsequently married). Custody of their son was granted to him.
When Mabel remarried in Dec.1900 Luton there are 4 separate entries for her in names of Mabel Percy, Mabel Warhurst, Mabel Moore and Mabel Carmichael!
Even with details of his supposed father I can still find nothing positive on Arthur (or whatever his name was) pre his marriage to Mabel in 1892.
Whoever 'Lottie' was on 1901 Census (which started all this off) although she is shown as 'married' to Arthur I don't believe any marriage had taken place and hope in a way she isn't Charlotte Roberts because can find nothing on 'Arthur' after 1901 in the 2 surnames we know he used nor a likely Charlotte/Lottie with these names.
Sounds like his whole life was an act and can't believe a word he says!
Annette