Just noticed that your Olton Hall is ending on Tuesday at 10ish in the morning. I've not sold anything on ebay but I am a buyer and generally the best prices are achieved when items end on Sundays between, say 7-9pm.
I know it's not all money money money but if everyone else is at it, you might aswell get your fair dues. Also, as you said, it's going towards the funding of a fantastic project!
Wouldn't bother changing the timing of this auction but just thought you might like to know for future listings on ebay.