So, then.
Following from this:
http://singletrackworld.com/forum/topic/central-heating-experts-why-are-my-pipes-banging
which was a plea for help to cure banging pipes since replacing radiators with new ones......
I added an update at the end of it, that basically says I have tried everything short of taking the floorboards up & looking for banging pipes that aren't secured correctly or are tight up against notches in the joists etc.
So, this was the job for today.
First of all, on the side of the house that we seem to be having the problem on, there is the main bedroom in one corner of the house with the radiator on the front external wall under the window. Next to this is a smaller bedroom that takes up the rest of that side of the house. The radiator in that room is on the same wall as in the main bedroom. Between the rooms is the airing cupboard with hot water tank, pump etc.
The main bedroom has got laminate down, so I thought I'd begin my assault on the other room which 'only' has varnished floorboards. Should be easy.
Hmmm. I didn' realise that they were tongue & grooved floorboards. So, getting one up near to the radiator proved tricky although I managed it in the end, although it did involve sawing through it to get it out.
Immediately visible were two runs of two pipes. And they were as loose as a whore's knickers. Moving them slightly caused a clanging, banging sound and I was feeling quite buoyant at this point that it was the cause of the noise. So, I secured them in place using pipe lagging to wedge them in place and see if it made the sound go away.
Here is a pic of the lifted board & the pipes just about visible at the top & bottom of the hole, as well as a pic to show the position of the radiator relative to the hole:
So, once secured I left it with the board lifted & stuck the heating on, feeling fairly smug that this would solve the problem...
It hasn't.
It seemed like it did as there was no noise for about 15 mins, but then the banging started. GGAAAAHHHH!!
I have just worked out that one set of visible pipes (that wasn't getting hot is) the feed to the hot/cold taps in the kitchen, so I will remove the lagging I have put around them, as they are now closely bound together & the hot one will warm up the cold feed and obviously isn't the cause of the problem.
So, I am back at square one. I can feel the pipe to the radiator in the smaller room is still vibrating with every clang, so the source can't be the area that was free to move, which I have now secured. It must be in another location, presumably under the floor in the main bedroom.......which is a complete ball ache, now that I know we have tongue & groove floorboards.
What is the logical reason for using tongue/groove floorboards? I just don't understand it. It makes it an absolute nightmare to work on anything that requires lifting them up.....I guess they are draught free......
Hmmmm, think it's time to hang head and go round to OH's Dad (retired plumber) who fitted the new rads and get his opinion....
Bugger, bum & arse.......
Words of sympathy & advice, greatly received..... 
