In 1976 a chap called Robert Relf (you can find his story via Google) was imprisoned under race relations legislation for offering his house for sale 'to an English family only'. I remember this well because the National Front demonstrated in his support outside Stafford Jail, and I counter-demonstrated against them.
I wrote to the Commission For Racial Equality a week ago about this. No word yet other than a formal acknowledgement.
The estate agents handling the sale are Engall Castle and Millichap.