Thanks for the replies chaps.
Nigel, with all due respect to you I don't think I'm over reacting, I have very hard water in my area - a brand new kettle will start scaling up from the first time I use it, so I can only imagine what's going on inside my heat exchangers etc...
I've used about 1200 litres of water since I backflushed my softener only to realise I had nothing in the salt pot to recharge it with.
The job I did today I was on 150ft and couldn't get it hot, my ninja runs hotter on its in-tank heater. 3 weeks ago I couldn't touch the wand because it was scorching my skin!
I'm having to crank it up to 350psi now whereas before 250psi was plenty. there's no longer that satisfying POP and a puff of steam when I open the wand valve, it's more like a phut and squirt.
Surely that's telling me something