Urgh, tried to use one of each voucher today in my local store.
Had anyone else had the issue where you've looked carefully at the shelf for any special Advantage card prices, offers etc, added up to the right amount to qualify, you scan things through, scan the advantage card, still says £10 total to pay, then when you scan the voucher for the extra points, magically the total is now £9.90, nyah nyah, your transaction doesn't qualify. I scanned the chocolate bar which I had picked up in case this happened, but the till didn't like that.
And of course, I was on a self-checkout till, it was lunchtime so there were about 8 people in the queue, 3 out of 4 of the tills (including mine) required 'attention' and there wasn't a staff member in sight.
When a bloke eventually did appear, he reset the tills and then fucked off again. Just in time for the till to do the same thing on my second transaction (to use the £5 spend voucher).
I have to admit, I walked out at that point. I have so many blister packs that one voucher is neither here nor there as I don't buy that much stuff in Boots.