Preamp K8021 - end of relays RY6

I bought and build 13 or 14 years ago a pre-amplifier Velleman K8021.
Unfortunately for a little while I have a trouble… At low level I lost left channel I already had this kind of trouble on other amplifier and in usually It’s the relays. But I would like to change my relays VR05051AS, I can’t find it on your web site.

Do you know where I can find this model or equivalent ?

Thanks

Stept