I've been working on fixing a radiator leak on my D1 and just did a DIY recore. I've been meaning to get around to this for about 10 years and never attempted this before, but it's a bit like household plumbing. Probably not much interest in this as most would use a rad specialist for this, but just in case, I made a video of it. See youtube link below (not sure I'm allowed to post links, but here goes anyhow, it's just there to help any others considering this or if someone fancies a challenge!)
https://youtu.be/5XnVwSM00Wg