Cant add extra's when booking on UK site

On looking to place a booking I noticed that there was no way you can add extras to the booking, I was in need to book a child seat and wanted to get the excess protection cover and no where on the booking could i do this, unlike the other major car rental companies. I have used Alamo before but using the US site which you are able to add these too. After 4 emails to customer services and no joy in getting a reply from the Luton Airport branch, I had to place the booking as the pricing was going up. The site needs to add these areas into the page, so the branches know to reserve these extra's (Baby / Child / booster seats, GPS, etc). As I have once gone to a location and found no seats available and spent 3 hours for them to get one from another branch. But as you can tell I like using Alamo, the staff are great and friendly and the cars are in excellent conditions. Will always use them, they just need to update there UK site to be able to do the extras at the same time as booking.