repairing/changing a fabia radio

Hi, I've had a Skoda fabia (W) for about 6 months now. Initially the radio was ok for a few weeks, but then it started to periodically do a channel search / change bass etc with no prompting from me. Leaving it off (had to be for a while) seemed to correct it temporarily.

After a new battery a month ago, and entering the code all was well for about a day, but now it says 'safe' every time it's turned on and if/when it gets to the enter code stage, it always displays 3 .. .. .. .. Entering eg 1 for the 1st character makes eg the 3rd & 4th characters randomly change ie it has a mind of its own again, so I can never get the correct code entered. It got a bit boring doing a 7 hour round trip last week-end in the quiet.

Any ideas?

If not, & having got a quote of