Have you tried turning the volume knob to input the digits? Then using next button for the next digit placement. Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/mark_b53a7494531bf96d
You can get Becker radio codes for £5 from this link, I have used them a few times for radios from any country and they are very quick and helpful: Car radio codes in Uxbridge London Gumtree