If you look at the "Waste Electrical and Electronic Equipment (WEEE)" legislation you will notice two things.
First, it is quite long and complicated, second is that there is a mandatory system of site inspections which you are not guaranteed to pass.
They insist on a "Pre-Application" site visit which means that before you can actually even apply for a licence you have to have your site for them to visit.
And they do this once a year.
I do not know about you but I can not afford to spend the investment necessary to take over a large industrial site, fit it out to the level necessary for operations, then have it sit idle for over a year while the paperwork is formalized.
This is not an industry they are going out of their way to encourage.
In point of fact, they are using the age-old civil servant method of control, making it almost impossible to run through the maze they have created.
There is a lot of scope for a charity to squeeze in between the lines of the legislation but as yet I have been too busy earning money to eat and keeping the lights turned on to pursue this line of inquiry further.
Also having worked as a fund coordinator for a cancer charity before I would not consider that a project you can legally or morally undertake on your own.
So the underlying problem of honest people to work with comes up again especially as you are harvesting what are considered national assets for a charitable activity not simply metals of high value.
https://www.legislation.gov.uk/uksi/2013/3113/contents/made