Small dealer failing in its duties

[Stubby Pete]

Firstly, not sure if this would be better in "Car Buying". Admin please move if inappropriate.

Long story short:
Bought a car from a small dealer for around £4k.
3 days later engine management light came on showing a catalytic converter fault.
Was told by dealer to keep driving, didn't effect performance so kept going.
Less than three months after purchase, broke down and would not run. BMW dealer wanted over £3,500 to repair.

After some "negotiation" dealer took it back to fix and just can't sort it out.

I've now asked for a full refund and they are not responding.

They have my car.
Over a little over 6 months, I have been without the car more than I've been able to use it.

Questions:
Is my request unreasonable?
How would be best to go about getting a reasonable solution? (Preferably without claims court etc)

My last communication gave them a deadline which has been breached, a polite reminder was sent....still no contact.

[BertBert]

Doesn't look like the dealer is being reasonable, but how are you trying to contact them? Phone or email? If the latter try the former.
Bert

[TooMany2cvs]

So they've had the car for three months, "fixing it"?

Drop any paperwork/spare keys round to them, and issue a court claim for the purchase price. They aren't playing ball, so that is your only option.