Re: EE and PAYG vermin
With a second mobile sim that has free 0800 numbers (giffgaff etc), use a company like 1899.com to get price per minute down to 1p (5p connection fee applies). You have to first phone a free 0800 number, then enter the number you want to call.
Quality isn't always great, but its good for call centre calls via mobile, where you're kept on hold for 10 minutes, so a 15p (10p+5p) charge, as opposed to £3.00 charge, then I just ask to be phoned back. The 1899 generated calls are billed separately/paid separately from your Mobile account.
Works well enough, can be a bit tedious at times though, when you just need to speak to someone quickly, where a three sim 3-2-1 sim is a better bet, where the call quality matters.