Per title… I regularly see people parked (sometimes several at once!) on the 1st roundabout to Abingdon Services on M74(n) J13 / A702.
See streetview: google.co.uk/maps/@55.50289 … KjvZGg!2e0
There’s a bin (just behind the passenger side of the wagon) on the roundabout, which suggests they KNOW people park there, maybe even encourage it?
So, is it legal, and does anyone do it? Is it just that you want/need a break but can’t be arsed going round another roundabout to the services? 
Would certainly need a break , the place in the link you are posting is AbingTon , South Lanarkshire , not Abingdon , Oxfordshire , they are only about 300 odd miles apart .
Hardly parking on the roundabout , at the side of it , leaving plenty room for everything else to pass , a thing that can be seen at other roundabouts off Mway slip roads .
Wouldn’t be the quietest of places though , & no markings or signs to discourage it .
Careful Casual Observer… AbingDon. That’s ‘Muckaway’s’ patch… Oxfordshire.
This is Scotland mate,you can park just about anywhere up here,no probs 
see Mintlaw, Parking on the roundabout where most reverse onto live lane. School bus stop, public toilets several shops. Maybe not motorway traffic but a busy roundabout.