If you aren't sure what to do, why not get an Ikea Antilop for now. They are 12 quid, plus 3 for the tray, and soo easy to clean. Very roomy, so you can use at the table till DD is 2 or more, or put a tray on for a little one.
That way you can always change your mind later, and not be too out of pocket.
Ikea do do a toddler high up chair thing too, but I haven't personally used it