As with a couple of The Saturdays previous singles I believe this is a Total no.1 Worthy single. But I think the main problem facing the Saturdays is that the single has been around for months now and the video also. People will either have got bored by the song or will already have downloaded it leaving no need/desire to buy it. They should release it digitally more promptly.
On the plus though they have their excellent reality show which I think could cement them more ardent fans. Hopefully! One other thing the Original version without Sean Paul is better in my opinion but I doubt his presence will harm them in the UK as his solo stuff has been quite popular.
But I'd say Sunday it will shoot to no.2 or no.3 but demand will quickly burn off towards midweek and it will end out the week much like 30 Days at the lower reaches of the Top 10. So Sunday figures will have it Top 5 but we can hope for better if they have some good appearances lined up.