Ah sorry by the way, I made the schoolboy error of using the 'Quick Reply' box at the bottom of the first page without noticing until later the other replies about Manx Telecom SIMs etc which I blithely duplicated. I've been mollycoddled by the RW forums that only let you post from the last page :-)
They're actually a little more sophisticated than you might expect. Both SIMs are permanently active (and therefore always searching for networks), but you select which SIM you want to use for outgoing calls/texts. It works surprisingly well.
I do recall Charlie mentioning his Irish SIM card and wonder if that might be worth investigating? Particularly if the calls are cheaper than the Manx Telecom 25p/13p rates. Charlie - I'm assuming that the phone number pattern is not the same as the UK's?? That's one advantage of Manx Telecom.
Martyn Price
North Leeds Fell Runners
I've not bothered to shop around as I've had the same O2 Eire SIM for years, but the roaming rates are here: http://www.o2online.ie/o2/roaming/zone.php?c=gb -- so it's about 30 Euro cents (say 25p) per minute for voice calls, 10c for a text. But you also have to pay 9c/min for incoming calls. And yes it is a +353 country code. (When sending a text, you have to remember to use the +44... format, but calls can start 07xxxx). I probably would have gone for the Manx Telecom one with its handy 07xxx UK-style numbers if they'd been available on prepay back then. Two other considerations though:
1. about once a year they have a special offer to double your top-up, so the costs are halved
2. the customer service people are very friendly and have really nice accents :-)