How do I rest the time on a Crasne & Viceroy clock?

I have the avove clock which went haywire on the summertime change. The radio time set is not correct. I left the clock without batteries for a few weeks and tried again. It reset to 12 o'clock and then picked up a time and set itself. Presently it is running two and a quarter hours slow. How can
I get the right time and correct chimes?