One photograph of Deborah Rose and Robert Plant, taken in May 2012, was in connection with the touring of the Dan Cassidy Swing Quartet. An additional photograph, again in a musical setting, was taken in 2013 during a visit with Ralph McTell who was on tour. (https://twitter.com/Ralph_McTell/status/389837440388960258/photo/1 ) Unsure of how and when they met but their first meeting might have taken place in a pub where Deborah Rose was singing. In an interview with Jimmy Buff of Radio Woodstock 100.1, Rose recounts:
I was singing it [Little Maggie} in a pub in Bewdley and then a certain person walked in and went “Hey, I was just listening to that song earlier today and I might record that for my new album.” And I said “Oh well, I might do it first.”(http://radiowoodstock.com/audio-on-demand-detail&cat_id=&song_id=2686137719&cat_name=&circle_id=5567# )
The first appearance of them in a non-musical setting occurred in January 2014 when they were vacationing in Cuba. A tourist who was at the same hotel, the Melia Buenavista, in Cayo Santa Maria, remarked:
We had a bonus this week, Robert Plant and his better half Deborah Rose were vacationing at the resort as well. Amazing couple, great stories and so kind to speak with everyone who recognized them.( http://www.tripadvisor.ca/ShowUserReviews-g670039-d1931078-r191738183-Melia_Buenavista-Cayo_Santa_Maria_Villa_Clara_Province_Cuba.html#)
So, the relationship began on or before January 2014. Other photographs taken at a fundraiser, organized by the Morgan Foundation, in June 2014 http://www.countrysmallholding.com/poultry/morgan_foundation_charity_golf_day_1_3654680
identified Ms. Rose as Deborah Hodgson, a name that she was known by when she performed at the Isle of Wight concert in 2009 (http://www.bbc.com/news/uk-england-hereford-worcester-17750415 ).