Final update:
My magazines arrived today all safe and sound without issue. Naturally I did the obligatory test fire and they all appear spot on so I can't complain on the product front.
My complaint from this experience would be that I had to pursue the company to find out if my order had been dispatched, which took a couple of emails to get a reply. I was then told (as per my previous update) that the item had been shipped. I attempted to use the tracking number provided a few times but with no luck, Royal Mail reporting to try again later on each attempt.
Anyway, my items turned up today and the postage label revealed that it hadn't actually been posted on the 9th but that it had in fact been posted on the 10th. In addition to this the tracking number I had originally been provided with didn't even remotely resemble that which was on the parcel. Said tracking number also confirmed that it was posted yesterday (10th).
In the defence of SAS they did end up sending it out by next day recorded delivery but I would much prefer honesty when dealing with a business. Now I realise that they got the package to me with a day to spare (reduces the stress levels a bit) and as such I really shouldn't be complaining but I can't help think "why not be honest?". Just a simple email of "Hi Frag, sorry we had some issues dispatching it today. In order to make sure it's with you in time and because we were unable to meet the agreed dispatch window we've sent it out to you next day delivery. Many thanks, SAS". Surely that would have been better?
But anyway, I've got my mag's and I'm more than happy with them. Despite the lack of honesty I'm also happy that SAS went to the trouble of sending it out with a higher priority dispatch method, something which I'm genuinely grateful for.
I suppose the big question is would I use SAS again? To be honest I don't know. If they'd been transparent then I'd definitely have to give it serious consideration but this lack of honesty makes me wary even though my experience was a positive one overall.