B
Bartdude
get a aga or stanley if you want hot water/heating better than rayburns, have a look at aga telford for 2nd hand ones
An Aga will only supply hot water,there's no heating option.
The main difference between Aga and Rayburn is that Aga is a true 100% heat storage cooker,always at a constant temperature. Rayburns are designed to idle at a lower temperature and be turned up when you require higher cooking heat.
When the central heating market started to take off it was Rayburn that first started producing models,starting with solid fuel of course and a whole host of other weird and wonderful models. The 480k with twin pressure jet burners started with the mk1 and 2,poorly designed appliances and the cause of grief for a lot of customers including the OP. The newer models are much improved and are now at the mk4 stage,and they're now offer good reliable performance. In my opinion the Rayburns are superior to Stanleys,much better construction and nobody does enamelling like Aga/Rayburn. Stanley is now owned by Aga too.
I've always felt that if possible a separate central heating boiler is the way to go and a range cooker for cooking only or hot water will cause less problems in the long run,but every house is different and for some situations the heating models provide an ideal solution. The key is getting the new Rayburn installed correctly,particularly in the case of the heating system,follow manufacturers instructions and you'll be fine.
I wouldn't recommend a second hand central heating model,the decent ones aren't old enough to be available,and a manufacturers warranty will be good for your peace of mind considering the problems you've had. When it comes to the other versions however there are lots of good reconditioned cookers around,the company old plumber linked too are good,but they're part of Aga and you pay for that. I'm sure you're Aga is great old plumb,it's a shame I wasn't on the forum when you refurbished it,might have been able to save you a few quid🙂🙂