As far as I’m aware he hasn’t been banned from the UK by the government, just various private venues by SJWs doing the usual trick of bullying anyone who doesn’t ideologically conform with boycotts and threats.
I would be very much surprised if anybody in HMG had even heard of Mr Graham before seeing media reports of this row.
(This has awakened long-dormant memories. In a previous incarnation as a born-again (or so I thought) teenager, I played a small part in the organisation of one of his father’s British rallies c.1960).