function validateMapForm(f){
 	if ( f.Type.options[f.Type.selectedIndex].value == '' ){
		alert('Please pick a type of place to find')
		return false;
	}
	
	if ( (f.addr3.value == '' && f.pc.value == '') || (f.addr3.value != '' && f.pc.value != '') ){
		alert('Please enter either a postcode OR a town.')
		return false;
	}
	
	return true;
}