Complex sentence: Princess Louise, Duchess of Argyll laid the foundation stone of Hellyer's buildings, which were designed in the Tudor Revival style using local stone and which consisted of a line of eight blocks accommodating 12 patients each and flanking a central chapel.
Split into simpler sentences: Princess Louise, Duchess of Argyll laid the foundation stone of these Hellyer buildings, which were designed in the Tudor Revival style using local stone. They consisted of a line of eight blocks accommodating twelve patients each and flanking a central chapel.