This will depend on the issue. However, many plumbers are also Gas Safe Registered, meaning they can undertake work on all aspects of boilers and central heating systems. It's best to look out for plumbers that display the badge of your boiler on their literature.
Humbie
Humbie is a district and also rural parish in East Lothian, Scotland depending on south-east of the region, about 10 miles (16 kilometres) south-west of Haddington and also 15 miles (24 kilometres) south-east of Edinburgh. Humbie as it is known today was formed as the outcome of the union between Keith Marischal and Keith Hundeby in 1618.