Hi Angela,
Yes, you normally apply from the country where you’re resident which sounds like it’s the UK. Things are moving a bit slower at the Portuguese consulates in the UK, as you can imagine, but hopefully they’ll speed up in the next few months.
I will pass your details onto a relocation company as this is one for the experts, but it sounds like your remote job could make you eligible for the D7 visa. Hopefully that’s the case.
As for the investment, this is probably still something you would be able to do on the D7, however, I think it would be good to speak to an accountant/tax advisor beforehand.