Many thanks for all the efforts and responses
I am fortunate that my late grandmother was interested in genealogy. She collected a mass of photos, albums, documents etc. Frustratingly she obviously knew who was in the albums but did not label any of them. I have managed to identify near enough all of them ... this one, however, remains a stubborn mystery.
The main candidates have been the Parsons family and Skyrme family, both of Hastings. But these have now been ruled out due to them being identified in other photos and not matching to the people in this album.
The album also includes a fox hunting meet, with one image identified as being taken in St. Albans. This brought forward Vice Admiral John Edric Blaxland as a candidate as he briefly lived in Harpenden during the early 1900s. However, there are no references to the Royal Navy in the album and he had no links to the Hastings area.
As has been suggested, I probably will have to write out a list of family members from the 1911 census and cross reference them in the hope that they actually were at that unidentified country house at that time. Of course the property might have been rented. Another possible candidate is the Wigan family who were hop merchants in London. I have identified photographs of the mainline of the family, but not of the younger siblings - big families with numerous offshoots. They were linked to numerous large houses.
Surprisingly the album contains absolutely no loose photographs at all. Every photo is still firmly glued to the pages. Unfortunately any potential secrets on the back shall remain hidden.
I will attach a photo of the St Albans hunt, and also two other photos. Most of the album is made up of such garden scenes. I looked to the lawn mower for clues, but it was a commonly produced brand. The woman is holding a copy of the Bystander, but again not much of a clue.
The St Albans photo is intriguing. The family obviously enjoyed hunting (guns clearly on show at the house) and riding. But compared to the identified locations St Albans seems a bit out of the way. There are several pictures of this hunt making its way through the countryside.