Absolutely agreed on all counts.
The point about teachers is also something I think is quite neglected today. A teacher with real-world experience of their subject is vastly better than someone who has known nothing of the world outside education. And that's of value far beyond the subject matter: they can provide career guidance and real-world perspectives of all kinds that less experienced teachers simply can't provide. Certainly some of the best teachers I had were those who had done real work.
Regarding the Chancellor of the Exchequer, I absolutely agree. But I think it should go further. I think all MPs should have direct experience of running a business and having to make payroll. Too many of them lack understanding of the reality of what a business is, and how the economy runs. It would temper some of the most extreme and dangerous actions, from taxation to social welfare spending. Too many think businesses are "rich" and can be taxed with impunity to pay for things of dubious benefit. It's easy to be profligate with other people's money if it seems like it's there for the taking. Experience might make them think about how to grow the economy to benefit us all, and reduce unnecessary expenditure. They might also think more carefully about supporting small businesses while ensuring large multinationals also pay their dues. I personally paid more corporation tax than several multinationals, despite earning less than the living wage.
For the first time, I set up and ran my own small consulting business for the past two years after being made redundant. (I'm also in the UK.) It was a small-time business with only one client for a couple of small contracts, and I since got a new permanent position. But the experience of having to do all the company registration, contract negotiation, invoicing, bookkeeping, dealing with accountants, paying corporation tax, and finally getting it all wound up was an invaluable experience which will likely be of great benefit in better understanding the businesses I work for. It gave me a proper appreciation of the realities of running a business, including all of the responsibilities you have to shoulder. I think every elected politician should have this experience. Every self-employed person in the country has a better understanding of the practical reality of economics and taxation than most of our politicians. And I think all politicians should be aware of the reality of what the rest of the country has to bear in response to the decisions they make.