I've flown, and stalled, a standard UK version MK.26 - it didn't strike me as lacking adequate aerodynamic stall warning, and the stall was only averagely unpleasant - not unlike a PA38. In the case you've quoted, that aeroplane was on final to land - not an aerobatic manoeuvre. Stall and overstress avoidance in high g manoeuvring rely also upon stick force per g, which is an additional warning.
Apart from which, the Mk.26b is a larger and more powerful aeroplane with, doubtless, subtly different characteristics anyhow.
Also, few overseas aeroplanes gain UK approval without some modification.
So, basically, I'd not read anything into that report with regard to aerobatic approvals in the UK.
G