We used Aptamil, but AR can cause constipation, so we used Comfort too and it suited DD just fine.
You will need a teat #2 or vari-flow teat since the formula is thicker. We used Tommee Tippee teat #2, the vari-flow seemed too fast but a lot of people prefer vari-flow, you can buy it at Mamas&Papas.
I used NAN AR but it's hard to find at super markets so I suggest you avoid it. I have heard very positive comments about Aprtamil AR which I see pretty much in all supermarkets...S26 AR is also readily available. Both are also available at C4 where they tend to be cheaper than Spinneys etc.