Thanks for input, Shane. Yes, I have that marriage ref, thanks, and agree no other obvious births around timescale.
At moment, more confused as to what became of Henry and Rebecca between 1906 and 1911, as not seeing any obvious death/s and/or emigration, nor seeing them in 1911 Census either. Mind you, on reading back through manual records, I see that when he married, their son said his father was 'Albert' and a 'butler'. Bit of a stretch from Henry Hugh to Albert, but then again, stranger things have happened. Given the occupation of father on birth cert as coachman and on marriage cert as butler though, I do wonder if he was in service to a family that moved around hence he travelled with them. If so, maybe a child arriving on the scene was not ideal for his job and hence the 'adoption'.