Now by all means put up an RCS for local destinations. That's not done enough IMO. In the ex A30 case a mileage RCS for Sutton Scotney would be acceptable (and cheaper - smaller sign) but not Stockbridge or Salisbury.
Not to mention Yeovil and Dorchester!
That said, I'm not quite sure why they ever declassified that bit of A30. All it does is send you the long way round to Bullington cross then down the old A34 which is not of any higher standard, and it's not as if any settlements were bypassed. Anyone in the know would use the old A30 every time - apart from anything else the Micheldever london bound slip road merge lane is long enough for you to join ther A303 without having a rocket strapped to the rear of your car
- or would go along the A303 to the A343 on the Andover Bypass then down the A343 (which of course was the original
You also dont see this on unlassified roads much either
I think they thought they were tidying things up when they redirected the A30 to Bullington Cross, or maybe that it would make it easier for A34 traffic to get onto the A30 without having a seperate junction near the services at Sutton Scotney, (or having a big detour to Popham Beacons/Mitcheldever). More cynically perhaps, by adding a third road to the junction it somehow gave better justification for the money spent rebuilding Bullington Cross! To me having A30 movements added just overcomplicates things and it would be a far simpler junction without the a30 in the mix. How much traffic uses the A34 to A30 movements anyhow?
That services sign, unlike the RCS going the other way would seem to be a hangover/survivor from the A30 days when more traffic would be using the road to get to the M3.