Halfords claim to be a reputable cycle supplier, so they should have made sure that you were ordering the correct size. My LBS would not take an order from me without checking that the bike would fit me. Similarly decent on-line suppliers usually ask you to provide a raft of measurements before they take your order.The Jogger said:I wish, under the scheme, the company I work for own the bike, until the end of the year, then you pay a nominal amount andd then it's yours, well mine!
I might try the halfords cycle2work helpline, they might change it But somehow I doubt it.
So you should definitely try to change the bike. Provided you haven't damaged it you could argue that you have just gone on the equivalent of a test ride.
Obviously you should stop using it at and once, and try and clean it up as much as possible.