The Disappearance of Alice Creed

Writer slash director J Blakeson (The Appointment) has made a film with only three characters and a handful of locations with a budget smaller than my bank account (if that is at all possible).
Danny (Martin Compston - Doomsday) and Vic (Eddie Marsan - Sherlock Holmes) shared a cell whilst at prison and discovered they had a lot in common. Now on the outside they've hatched a plan to kidnap the daughter of a wealthy man and hold her for ransom. They'd collect lots of money, let the girl go and before you can say 'Tahiti sounds nice' the two would flee the country and start working on a tan worthy of any Dancing With The Stars competitor.
The kidnapee is Alice Creed (Gemma Arterton - Clash Of The Titans), a very attractive girl with well manicured nails and way too much eyeliner.
Danny and Vic are meticulous with their movements; every step has been thoroughly thought out - any clothes worn outside the flat where Alice is being kept are worn once then discarded, multiple mobile phones are purchased, the walls of her room are soundproofed. Alices' hands are cuffed, her feet bound, her mouth gagged and her head covered by a cloth bag. She ain't going anywhere.
While Vic is in charge of making contact with Alice's father (sending photos and videos of her, and organising the ransom drop) Danny is left behind to keep an eye on their captive.
What, as they often say, could possibly go wrong?
As the movie progresses we begin to pick up hints about the relationships between the characters. The first reveal was a wee bit predictable but the second reveal seemed rather forced - almost like Blakeson was saying 'so you picked the first one easily but I bet you didn't pick this one, HAHAHA, I mock you mockingly!' Adding to that, that latter reveal didn't have a whole lot of credibility - perhaps that was due to casting?
While there are more twists to come, and as entertaining as they are, the ending may not be of any surprise.
I'm still undecided about this film; there were parts that really worked and parts that annoyed me. If someone has recently tried to kill you and you've got a chance to kill them are you going to wait while they recite the complete works of Shakespeare (OK so that's an exaggeration but you get my drift) or are you going to bloody shoot them as fast as you can???
Arterton was very good; she must have been so uncomfortable during this shoot having to be strapped to a bed for hours on end. Maybe they can have an Endurance Award at the BATFAs just for her?
Overall I enjoyed the premise, I'm just not sure about the execution...
Things I learnt: bollcoks to getting hit by a bus, always wear clean underwear in case you get kidnapped; shoot first, ask questions later; always have a spare set of keys.
Interesting.
Six out of ten.