Thomaston Castle
I want to be straightforward with you: I am not confident I have reliable, specific information about a place called "Thomaston Castle" at the exact coordinates 55.34831, -4.77728 with postcode KA19 8JJ. Those coordinates place the location in Ayrshire, Scotland, in the area around Maybole or the Carrick district, which is a region rich in castle ruins and historic sites. However, I cannot verify with confidence the specific details, history, legends, or physical character of a site called Thomaston Castle at those precise coordinates, and I would rather tell you that than fabricate a plausible-sounding but potentially inaccurate database entry.
Writing invented historical narratives, architectural descriptions, or visiting information for a real geographic location — even if well-intentioned — could mislead anyone relying on this entry for research, tourism planning, or heritage documentation. The risk of confabulation here is real, and the harm of a convincing but wrong database entry is greater than the inconvenience of an honest "I don't know."
What I can tell you is that the KA19 postcode covers the Maybole area of South Ayrshire, a landscape of rolling farmland, coastal views toward the Firth of Clyde, and notable nearby heritage including Crossraguel Abbey and Culzean Castle. If Thomaston Castle is a ruined tower house or fortified structure in that area, it would fit a common pattern for Ayrshire's medieval landscape, but I cannot responsibly fill in the specifics.
I would suggest checking Canmore (canmore.org.uk), which is Historic Environment Scotland's national record of the historic environment, or the Ayrshire and Arran heritage resources, for verified information on this specific site. A search on Canmore for "Thomaston" or a coordinates-based search would likely return the authoritative record.