Ooo - I can't be havin' with Ogdon.

The man just didn't seem able to float a delicate pianissimo.   On the (several) recordings I have heard he always seemed to be projecting to the rear of the hall, if you know what I mean.  His much vaunted Shostakovich Piano concerto #2 on EMI is a fine example - excellent fast movements (for the most part) but the sublime slow mvt just lacks delicacy and sensitivity to my ears.
Rather good at the barnstorming stuff, though!

'Britain's greatest ever classical pianist' ? - I think not.

Curzon in his younger days, perhaps, Stephen Hough, John Lill may be on the candidate list.

But Ogdon is insufficiently rounded a musician for me.
I suspect his awful problems with mental illness and tragically early death have contributed to the 'mystique'.