Really??
I've not heard of any such thing!
The only "minimum order" mentioned on their website is GBP 10.00 for credit card orders if you want free next-day delivery.
If you have a trade account, there is no minimum order - or there wasn't last time I tried, and I've had no notification to the contrary.

Anyhow, surely you could manage to "pad" an order out to 20 quid?! - buy some batteries, or something!

Have you tried Rapid or Arrow?

I can't help you for a couple of weeks, but if you're still stuck by then drop me a line - I may be able to order them for you.

Andy Neil,
Antronics Ltd,
Basingstoke.