sounding much like they were saying :
You want an hour of driving test.
To include motorway, that means a maximum of twenty minutes - guaranteed, all day, every day, from every test centre in the country - to the nearest bit of motorway.
Twenty there, ten down the motorway, ten back, twenty back - that's your hour.
It is not going to work for a VERY sizable percentage of test centres.
I took my test in Buxton. The nearest bit of motorway is the Manchester Ring, the M60, just the other side of Stockport. That's nearly 20 miles away. That's reasonably handy, compared to some.
Norwich, as an example, is 60 miles from the nearest bit of motorway, the end of the M11 at Cambridge. Each way.
Aberystwyth is 90 miles from the nearest bit of motorway, the M50 at Ross on Wye. Each way.
Inverness is over 110 miles from the nearest bit of motorway, the M90 at Perth. Each way.
By all means have a separate motorway test that you have to take to "upgrade" your licence before you can drive on motorways - but I'm really not sure that's the biggest part of the problem.
I did do a separate motorway lesson with my instructor after pbutting my test - we went to the nearest-easiest bit of Motorway to where I was living, about 25+ miles each way - Just getting there and back was over half of a two hour lesson.