Edited OP
Thanks all for your responses, all sorted.
Does not sound like holding deposits are a thing which I find interesting as I have had other dealers offering to hold the car if a deposit is paid and they assured me it was 100% refundable.
I feel like dealers are being sneaky if they send you a contract to sign after telling you this and not disclosing its a purchase contract and the 3 day cooling off period and also not having it available for viewing in this period.
You clearly changed your mind about purchasing the vehicle after the cooling off period and you also made it clear to the dealer that that was the case - not because you were not happy with the car.
Had you actually viewed and test drove the car and said that you didn't like it, I'd say that your chances of a refund would've been higher.