We bought sim cards from Woolworths in Perth WA – go here – www.woolworthsglobalroaming.com.au. 2 cards cost us $58.00 and on balance they are a good idea. They offer the purchase of a local number for your family/friends to call you by dialling a landline number (you pay a nominal amount ($16 for 2 months) for the rental. The idea is to place the sim card into your own mobile when you are overseas and use any of the available carriers. Generally, it defaulted to Vodafone. It worked in every country I was in (UK, France and Germany) although not too well (in some situations there was no service). I think they only work when you are in a city area. It is a bit dodgy in the country. The cost of phone calls is very cheap. Would I use it again. Yes if I needed to have a local number in WA for family to contact us. No if I wanted to use the service available in the country I was in and that means buying a sim card for that country or seeing if a global roaming card was also available. I cannot comment on the availability of a global roaming card for UK and Europe, I suspect not.
Dialling a number is interesting. You must dial 001144 (then the number you want) to get in touch in UK. To dial a number in Australia you dial 001161 (then the number you want). Most times it worked perfectly. I also received phone calls from my Mum on my mobile – clear as a bell.
I still have credit on the sim cards and after returning to WA I tried using them in the two tablets we have. Either the tablets don’t suit the cards or the cards don’t work.