Just been out for a blast, back in the office 4th floor overlooking car park - can unlock/relock the car at range of some 80 metres !!. (This is without the Clarkson 'blipper to head' range extender).
If your " blipper" is on 433mhz the car park may be acting as a wave guite. The range in free space may be less. Having said that the effective range at UHF is line of site anyway, most car systems are limited by very poor antennas at both recieve and transmit ends.
I agree the Meta ones are hopeless. A quick look at the circuit board shows why. Not the best desgin, but it prevents the key thief from finding the car in a car park.
I have to virtually hold the blipper in the car to get it to work!