Just saw this in the Metro (15/10/2015) this morning. Asda have their toy promotion on and set 66523 has £10 knocked off the “retail price”.
LEGO City Super Sets normally represent good value for money, so when you look at 60060 Car Transporter has a RRP of £24.99, the other two are at least £7.99, so you do save the £10 – which is essentially a free set. However, I would hesitate if the price was brought back up to £40 as that is what the retail for all three sets actually is.
Having looked at the Brickset entry, there is no given market guide price and this will be limited availability.
If you do stumble upon this set in the madness that is Asda, well worth grabbing on at this price to add to your Cityscape or collection.