Glitch with radio buttons on search

Hope someone can help with this.

Basically I did a site a year or so ago, that was all working fine.

However, they changed the hosting, moved all the files across, and exported the database.

Somewhere along the way, a few glitches cropped up - for example the search results page going AWOL, and some SQL error messages cropping up.

So I've been trying to get them to sort it, and am now having to look at the site again myself.

I've got one glitch outstanding - on the page here :

www.mph.uk.com

There's a basic search on the right hand side - where users can select cars or vans as well as a make of vehicle.

The problem is that the radio buttons don't seem to work - if one is checked, and you try to check the other one, they both end up checked instead of swapping.

The radio buttons were originally :

<input type="radio" name="VehicleType" value="Car" id="VehicleType_0" class="tickbox"/>

and

<input type="radio" name="VehicleType2" value="Van" id="VehicleType_1" class="tickbox"/>

With this code on the results page that references them :

$WADbSearch1->addComparisonFromCheck("Category","VehicleType","Car","","AND","= ","=",0);
$WADbSearch1->addComparisonFromCheck("Category","VehicleType2","Van","","AND"," =","=",0);

Which I'm sure worked when I did it originally.

So going back to first principles, I made the name of each radio button the same ("VehicleType"), and that fixed them so that they at least changed when each is selected.

But then the search wouldn't working - it only returned cars, but not vans.

If anyone could let me know how to fix this, that would be much appreciated.

Cheers.