SimonG has the nickname Mr Shouty. He has his own way of communicating and in this case he certainly got his point across. I suppose my attitude is somewhat different as you need qualifications to do this that and the other on a heating system, but none at all to work on the brakes on your van.
Well... now you mention it
Not entirely true, but depends where you are. Anywhere near Machynlleth, there are LOADS of people installing woodburners with backboilers partly due to the influence of the Centre for Alternative Technology over the years. You could try seeing who is installing woodburners as many of them will have some idea about solid fuel wet systems. Or try contacting the solid fuel association? In fairness, I have seen a professionally-installed system where someone ran a Fortic type cylinder off a woodburner (direct without a coil) which would have been okay in a soft water area, but then they also added a steel radiator which airlocked every time the household lit the stove, so I do agree a householder needs to check that professional installers know their trade.
Yeah. Gas Safe installers aren't always the best plumbers. It would be better in some respects if the two trades were either totally combined or totally separated. Though, if we follow your thinking about the 'old boys' and experience, he's probably been installing gas pipes like that for 30 years and yet to have one leak. My own house has a gas pipe built into a brick wall and it's been like that since 1988, and possibly earlier. It's wrong but textbook says it's illegal, experience says it still works and gas installers who have visited the property say it's running under grandfather rights so long as it isn't leaking.
I can understand why you may have trouble finding good installers - I personally like the one-to-one contact with customers and dislike the fact that many builders underestimate the cost of plumbing and then push for sub-standard work so they can fit within their budget, need jobs done quickly and then postpone the day before you're supposed to start work, and the fact that in my experience they are the worst payers which has put me off rather - in fact I now refuse to work for anyone but the end customer (I may not be the only one?). Plenty of direct work for homeowners, so I'm not available for builders and I know many others in my situation are backlogged with work and would struggle to fit work for builders in. Very sad for builders who might be excellent customers that they are probably tarred with the same brush. Perhaps you just need to bit the bullet and employ directly (if that's an option, which I'm assuming it isn't else you'd have already done it)?
Not legally required!
Not required... if the washing machine instructions state backflow protection is integrated in the machine and WRAS approved hoses are used to connect. In practice, I always fit check valves because the person installing the machine generally doesn't understand this and two valves are better than none if one is required.
And are under pressure to lift pass rates, even if they are council-owned because low pass rates suggest bad teachers or taking on the wrong students (even when they may also mean the college actually rightly fails those who shouldn't pass). The actual problem is that the NVQ system has very low hurdles and you can legitimately pass while knowing very little.
You don't need a teaching degree to teach NVQ plumbing, but being able to teach and being able to do are different skill sets. Some people can do the job but couldn't teach for toffee. And actually, I know some old boys who still use lead solder on mains water because 'it's better' (which may be the case, but it's also illegal), don't understand how to flush out a new heating system properly and then blame the new boilers because the heat exchangers block up 'new boilers aren't reliable' they say... but their competition installs boilers that ARE reliable which suggests the problem is them and not the boilers. Sometimes experienced people spend their lives improving and learning, and sometimes they just keep doing the same thing they were taught as apprentices - it's not the same for all people.
Yeah. I see where you are coming from. This site looks moderately interesting. Would suggest if you are going to pursue this line of thought, you have a read on this
Useful Guide: Boiler stoves & central heating PLUS LINK TO BEST BOILER STOVES - https://www.stovefitterswarehouse.co.uk/products/useful-guide-air-vent-boiler-stoves-centra-heating (note the article on heat sink radiators shows how you can have a heat sink without a cylinder) and consider your cylinder to be a secondary use of the heat as you cannot rely on anything that is on a drop. Then do a proper sketch and go through the install by non-competent person and notify to Building Control so it's checked by someone who, while they may have read it in a textbook, should at least have enough concern for his own backside that he won't sign it off until he (or she) is 100% satisfied it is safe. It's not a terribly expensive route to take.