I have been on the Sandafayre mailing list for some years and get all the new listings of Flags and Cinderellas. But I find them too expensive and have rarely purchased.
However, they are an A1 firm and are great to deal with and talk to. I find it hard to believe they would offer such an amount without reason...or did they give a reason? What did they say about the condition of the stamps ? Did they offer any advice ?
I met the team at London 2010 and they were very helpful. They even let me 'borrow' one of their prized possessions, an inflation-era cover, one of the worlds tallest !

Can we see some scans or pics of what are in the albums ?
Londonbus1