Absolutely not, Rosemary doesn't like acid soil conditions. If they've been in the pots for a while, they may be rootbound - turn them out and pot them up into something larger if that's the case. Other causes are underwatering, so check the rootball for dryness, but also check for signs of infestation or other signs of disease.

Mine was in a pot for years with multi-purpose compost. A cutting I gave to my neighbour is huge and bushy in her garden with normal garden soil.

It's a Mediterranean plant - needs full sun and well-drained soil. Otherwise it thrives on 'benign neglect' and does better in poor soil than anything rich - that's why it does well in pots after a couple of years.

Thank you all for your help :)