Thank you @littlescribe for taking your time to try and help me out :). I appreciate it. And different perspective is always good.

Now, I have a feeling I might be just defending the choice I'm most likely making for the sake of not feeling shit about it ... but rationally my soon-to-be choice makes sense. I still have a day or two to completely decide I'd say and I'll go for a run and meditate to get more clarity, but here's my reply to you so far :). Maybe I'll come back tomorrow and change my mind, but right now :

1. Yes, there's plenty of pen testing jobs. As there's not many people who actually have that skill. Not all of them are made equal though, and lots of them are in UK where I don't think I want to go back to. At least not London. I think I'd be miserable there. Though maybe it'll be the same in this other city. But from my little research it seems better in areas I care about. But only real experience can tell.

2. I agree. But I am not planning on staying there forever. I think year and a half is my max. But that proably goes for whatever I'd do and wherever I'd end up. But I have an option to quit anytime within first three months. So I am not taking that as a "Oh, YES, A CORPORATION GAVE ME A JOB, WHAT A LUCKY GUY I am", more as the opposite, as can be evident form my title :D. So I am not really planning on building my corporate career and sucking up to people. THat'd make me disgusted with myself and feeling like I completely left my values behind. That's just not gonna happen. It can't happen.

And one of the reasons why I'm pissed with corporate jobs is the fact that they support government and how much money goes to government from "my work" . I think that really pisses me off.

3 ) That's what I actualyl don't know. I might hate development. I never really done it for a long sustainable period of times. It's more like some side projects, or ocasional contracts where I coded something but it wasn't that long and even that sometimes pissed me off and I had to take a break. And that I'd say still wasn't the real deal and full "cycle" of development. So it might be actually worse :D. Honestly, I don't know. So I just have to try both in a real setting I'd say.

4)Yup, I have some people who haven't replied yet and one that seemed interested and they seemed interesting. Though that brings other complications, too (like two hour commute once or twice a week, lack of in person guidance, etc.) and as they didn't reply yet, the answer could be no. And I can still look for some other opportunities.
I can quit in first three months any time. But I am honestly completely out of money. So even those three months would actually help me. Plus it'd give me a chance to see if I want to do that part, if I wanna take that pill. Cause if I take a Dev job I'm signing up for more.

5 ) Yea, probably. Though it's not a romantic interest. And maybe there's a way to keep that going anyway as I might be coming back here once a month or whatever. It's not that far by train.

Again, thank you :). I'll think about this more as I said and maybe I'll come back with more or different answer.
But what I wrote above are my justifications and logical reasons why I shuld go for it.
And part of my gut also tells me I should do pen-testing rater than development, or at least give it a second chance outside of UK.