New Zealand v England: Alastair Cook challenges players to step up to land place in Champions Trophy squad England have obvious credentials for a successful campaign when the world arrives on their doorstep in June. Cook is encouraged by their form under his captaincy over the last two years, and last month's 3-2 defeat in India - new limited-overs coach Ashley Giles' first in charge - was an improvement on two previous 5-0 whitewashes in that country. Giles' appointment, however, to replace Andy Flower and allow the latter to concentrate on Test matches, puts England in a transitional phase. "Clearly, it changed the balance a little bit when Ashley Giles took over as coach only in January," said Cook. We were very settled with Andy Flower. So things have changed a little bit there, with the change in management. But we're (still) a very settled squad in one-day cricket, and have been playing very well for quite a long period of time now. The return of three first-choice players - Graeme Swann, James Anderson and Jonathan Trott - after being rested for India also means some tough decisions will have to be taken about who makes way. "We do have slight selection headaches," added Cook. But as coach and captain, that's what you want and need to produce a good squad. Cook confirmed it has already been decided that Jos Buttler will remain as wicketkeeper ahead of Jonny Bairstow, having been given the gloves for the Twenty20 series against New Zealand which England sealed yesterday with an impressive 10-wicket win in Wellington. Bairstow missed England's last Twenty20 in India before Christmas, and then the five ODIs back there last month, because of a family illness - and returned to discover Buttler, elevated in his absence to keep wicket ahead of Craig Kieswetter in 50-over cricket, would also do the job in the sprint format. Cook still envisages a possible role for Bairstow in the first-choice team, though, as a specialist batsman. "Jonny's played as a batter in Test match cricket, and done well," he said. Whoever takes part tomorrow will have to do so without the customary benefit of a day of nets preparation, against opponents Cook describes as "dangerous" and in a country where England have lost their last two ODI series 3-2 and 3-1. "I don't think I've played a one-day game, or any game, for England where we haven't had a practice as a squad before," Cook said. It's not ideal. But it's the same for both sides, and we've just got to get on with it. We'll have to be right on the money. The stats prove how hard it is for an English side to win a one-day series over here. One man who will not be able to press his Champions Trophy claims here is Alex Hales, as yet uncapped in ODIs. He and his fellow opener Michael Lumb made a mockery of the Twenty20 target set by the Kiwis yesterday - smashing nine sixes between them in a record, unbroken stand of 143 which finished the deciding match more than seven overs early. Yet Hales, and Lumb for that matter, will not be able to see their stock rise either at the Indian Premier League after their county Nottinghamshire refused to allow them to take part in a competition which clashes with the start of the English season. It is potentially a toxic topic for many big-hitting England players, and one Cook concedes may feature for some in future contract talks. "Nottinghamshire have made Alex Hales unavailable to play (IPL), so that's not really anything to do with the ECB," he said. Of course when contracts come up for discussion, for renewal, there will always be the issue of availability and money. This is not really the time for me to talk about it ... there will be another time to sit around the table with everyone and speak about it there. As players, we've got to remember how lucky we are to be playing for England.