A big thanks to HCP for helping me get trough the many requests... Couldn't do this without a little help from time to time 
It looks like this is the only question left open at the moment:
Good thing I have not taken action yet, cheers for the heads up!
I don't know then what the same inputs means, I thought it would be the address and amount you 'put in', but I'm just a scrub.
I'll create a double spending transaction for you... The only thing i wanted to ask: could you tell me which output value i can take the extra fee from? You're funding 1Nejxrk4Y9Q2eQ6YTd3hMi46uSnnN4Ghbn and 3AbZaaKj4ZVomw4YKTTpraqQYbaesByTpJ, i'll have to reduce one of these outputs to leave room for a bigger fee... It's up to you to pick witch one.
Once you tell me where to take the fee from, i'll create an unsigned transaction, since you moved to electrum, you *should* be able to sign said transaction with your electrum wallet and broadcast it afterwards. It's been a while since i last did this, so i hope it still works, but i don't think it'll be a big problem
It looks like this is the only question left open at the moment:
If I understand correctly, I now have to create a new transaction from Electrum. I enter the same address in 'pay to' and the same amount. Then send the transaction and broadcast it? Is that all?
No. Double spending requires that you use the same inputs... If you just create a new transaction without knowing what you're doing, you could spend "different" coins and end up sending 2 payments! Best wait for mocacinno to help! Good thing I have not taken action yet, cheers for the heads up!
I don't know then what the same inputs means, I thought it would be the address and amount you 'put in', but I'm just a scrub.
I'll create a double spending transaction for you... The only thing i wanted to ask: could you tell me which output value i can take the extra fee from? You're funding 1Nejxrk4Y9Q2eQ6YTd3hMi46uSnnN4Ghbn and 3AbZaaKj4ZVomw4YKTTpraqQYbaesByTpJ, i'll have to reduce one of these outputs to leave room for a bigger fee... It's up to you to pick witch one.
Once you tell me where to take the fee from, i'll create an unsigned transaction, since you moved to electrum, you *should* be able to sign said transaction with your electrum wallet and broadcast it afterwards. It's been a while since i last did this, so i hope it still works, but i don't think it'll be a big problem
I do appreciate you want to do this for me, but if you don't mind too much, I would prefer to learn how to do this myself.
If you rather just handle this one for me, around 700sat/byte (1.5mBTC) is what Electrum automatically puts the fee on. This is fine if you think that is what it takes at the moment. Take it from 1Nejxrk4Y9Q2eQ6YTd3hMi46uSnnN4Ghbn. I do see a Sign and Broadcast button when I preview a transaction, so I should be able to handle it from there.
Thanks again.