Many problems that people have with their heating is due to the radiators themselves. A common complaint is that radiators fail to heat up or they do not heat up evenly. The usual cause of this is that air is trapped within the system somewhere. In this case you will need to bleed the radiator to allow the air to escape. This is actually something that you can easily do yourself, you can get keys for doing this very cheaply, and there are videos online explaining how to do it.
Sometimes heating problems can be caused by the pipes themselves. It may be that you need to replace the pipes or the pipe fittings. Typically, copper pipe fittings like these https://watkinspowis.co.uk/products/copper-pipe-fittings-and-press-systems can be used for making repairs to heating pipes, but it is important that you get a professional to do this for you.
It may be the boiler itself that is causing the problem with your heating. If it is turning off, failing to heat up or making strange noises, these are all signs that you should have a professional heating engineer come and take a look at it and make repairs. A heating engineer should be corgi registered, as if this type of job is done wrong it can be very dangerous, so do not ever attempt to fix your boiler yourself, even if you think you know what is wrong with it.