Hi mate,
No worries. I don’t have air here to test them I’d have to go to my local site, and I won’t get that done in your timeframe, sorry! Plus if I test them and they are all working fine I’d be asking for more for them.
Btw I’d send Royal Mail second class recorded, it says on their website that they aim for three days delivery.
Maybe you can borrow a system from someone for this weekend, guys at walkons often have spares, or sites usually have loads of extras for their site markers.
Thanks,
Al...