Hi Kevin. Sorry for the delay in responding. I do still have the original valves that Alan Kendal supplied with the Monos, so I have a backup if one of my current Mullards fails. But if you found something that sounds rather good, I'd be interested. Perhaps you could tell me how much you'd like for them and we could work out how to get them to me - post I guess, or we could meet up in, say, Montauban for a coffee and a chat. I could pay by French cheque or bank transfer to a UK bank or a couple of bottles of Chateau Nottooshabby. Let me know. I'll keep an eye out for an AT20SLa too.