These days slip roads are plenty long enough for any car to build up to motorway or A road speeds before joining the carriageway, but how many times do you see driver almost afraid to join or braking almost to a standstill and then joining. Lots of bad and indecisive drivers on the roads.
As for the MG Hs they’ve definitely improved over the years but it would have to be no AP or even cash back to chose it over other suvs on the scheme.