Form Select problem in IE7

<form class="foxycart" action="https://mysubdomain.foxycart.com/cart" method="post" accept-charset="utf-8">
<input type="hidden" name="name" value="[*pagetitle*]" />
<input type="hidden" name="price" value="[*product_price*]" />
<input type="hidden" name="code" value="[*product_code*]" />
<input type="hidden" name="weight" value="[*product_weight*]" />



<label class="label_left">Size</label>
<select name="size">
	<option value="mini_pony">Mini Pony (pair) £24.99</option>
	<option value="pony">Pony (pair) £24.99</option>
	<option value="cob{p+5}">Cob (pair) £29.99</option>
	<option value="horse{p+5}">Horse (pair) £29.99</option>
	<option value="mini_pony_set{p+20.99}">Mini Pony (set) £45.98</option>
	<option value="pony_set">Pony (set) £45.98</option>
	<option value="cob{p+24.99}">Cob (set) £49.98</option>
	<option value="Cob_Horse_Mixed_Set{p+24.99}">Cob + Horse (set) £49.98</option>
	<option value="Horse_Set{p+24.99}">Horse (set) £49.98</option>
</select>


<label class="label_left">Colour</label>
<select name="colour">
	<option value="yellow">Yellow</option>
	<option value="orange">Orange</option>
	<option value="pink">Pink</option>
	<option value="black">Black</option>
</select>



<input type="submit" name="Add to Cart" value="Add to Cart" class="submit" />
</form>

return '<br />Browser: ' .$_SERVER['HTTP_USER_AGENT'];