I found these helpful videos on YouTube about boiler/central heating maintenance. www(.)youtube(.)com/playlist?list=PLriVNAkwBStZ31a3r_wA1h8bjzVnFScu2
Its a great resource for troubleshooting problems before calling an engineer. They cover everything from frozen pipes to bleeding radiators and even a jargon buster so you don't get tangled up in technical language.
After all now's probably the best time to check that everything in working order now before it gets too cold!