Thanks. The wallet I sent it from is an old Android one with very few features, so it doesn't have a CPFP feature.
CPFP can be done from the
receiving wallet, not the old Android Bitcoin Wallet.
I've tried that Ian Coleman link and none of the private keys provided will be accepted by other apps. I'd love to be able to get Electrum to accept the 12 word seed phrase but it won't do it.
I haven't tried it, but
this looks promising (again: use it
offline!). Given that you say you have 12 words already, did you follow this procedure?
Note that you don't have to try importing the private key from Ian Coleman to check, you only need to check if Ian Coleman's script shows 1Bt2ZMR523WZTRQPDuse9gG4yhAW61Nuhi. If it does, Electrum will accept it's private key.
Thanks for the links. The Github Gist above won't install as the build process fails.
As for the Ian Coleman tool, it's a great resource but it only provides master private keys - it only shows public/private keys for newly generated addresses. There's no way to find the private key for that specific address above. I can keep clicking 'more' and regenerate address pairs, but how many addresses can be generated? Millions? Not sure.
Edit: I've been successfully able to import the receiving wallet address into Electrum - how do I RBF or CPFP the stuck transaction when it doesn't appear in the list of transactions? It doesn't even import the wallet as if it's adding to the addresses - it makes it seem that it's sending the transaction to itself?