Old Town stone often wants slender sightlines and colours that sit with sandstone. Timber can deliver that look, with a maintenance cycle that owners need to accept. Modern UPVC profiles have narrowed; on the right elevation they read calmly from the street. Neither option is “correct” for every plot on the rock.
Later houses in St Ninians, Bannockburn and Riverside usually take UPVC without fighting the architecture. Regular openings, rendered or brick surrounds, and matching doors make a coherent package. Timber remains a fair choice where owners prefer it and will look after paint or stain.
This article is a comparison, not a second service page. For supply and fitting of UPVC units, use UPVC windows. A survey still decides frame depth, glass and ventilation for your openings — we do not invent legal requirements here.