Here is a list of London Songwriters recommended songwriting resources. There is nothing here that we have not personally used and found useful. Some of the links give commission and help to keep our community running.
Transcribe! is a transcription program which allows you to loop, EQ, slow down or transpose songs so that you can work them out yourself without relying on dodgy or non-existent internet tabs. It can also detect which notes are being sounded at any point in time on a piano keyboard layout. I have personally used this for the last 10 years and with this link you get a free 30-day full-featured trial.