Hello Eric, Have just come across your message which is now 5 years old so hope you are still looking.
My great grandmother was the sister of Jane Maslin who, it appears, died in 1900 leaving children. Amongst them were Rennie born c1889 who was taken in by his uncle David Maslin (see 1901 census). My mother and her mother remembered Rennie and Mornington Offen visiting their uncle Dave which ties in with your reference to Mournie. The other children appear to have been put into North Surrey District School and are listed on 1901 census as paupers born Lewisham:- Kate 12, Louis (sic) 10,Momington (sic) 4, Frank 8.
1911 census has Surrender Offen, nephew, age 11 living with David Maslin so assume he is also Jane`s child.
Kate appears to have married Herbert W. Nuth and an Albert W. Nuth was born Q/E March 1915 Greenwich district 1d 1961. It looks like he died aged 73 in 1985 in Poole, Dorset. If he has offspring and you can trace them perhaps they still have Offen links?
Lastly, when I was at the National Archive looking at WW1 records in 2007, I chanced upon the Offen name. Some of this was hard to read so bear with me:-
George Offen, born Rotherhithe, 29 years 240 days, labourer, 5`8" tall, chest 37" with 2" expansion. Florid complexion, dark brown eyes and brown hair, slight varicose vein left leg. Many small sicatrice following boils. Small scar middle finger left hand. Church of England. British Expeditionary Force 26/8/1914, gunner 87537 Royal Field Artillery. Address 43 Por....eave Road, Lower Sydenham. Done for gambling in the ...tent 26/11/1914, Shorncliffe, Folkestone 7 dasy confined to barracks. AWOL 10pm 14/3/1915 till apprehended by local civil police at Lower Sydenham on 16/3. 6 days CB.
Now, the bit most interesting to you. A letter from Miss Louis (sic) Offen enquiring after her brother from whom she had not heard for too long. The address was Plunginton Hotel, Fulwood near Preston, Lancashire. The hotel still exists.
It isn`t much but hope this adds a little colour to your tree.