High chair which converts to booster seat

[TeddyRuxpin]

Is there such a thing? Preferably able to fold flat(ish).
DD is 20 months and her current high chair needs replaced but she is still at the throwing food stage so eats mainly in the kitchen for easy clearing up.

Ideally I'd like to have her eating at the dining table soon, so a booster seat seems a good option but I'd like one that can also be used as a high chair if needed so that she can still eat in the kitchen at breakfast and lunchtime.
We have a breakfast bar but it's so high that a booster seat on a dining chair wouldn't reach to it.

Also, can anyone tell me if booster seats can sit on the floor when in use or would it be too unsteady?

Maybe one of the ones that strap onto a chair but with a tray also. We had a chicco one, so you could have the tray on with it on a chair in the kitchen or tray off at the table. Would that work. The one we had did fold flat to go away or take to pub/ restaurants or people's houses.

I don't know of a product which will do what you are describing. however I like the Safety 1st Booster seat which can strap onto a chair and it is only £12. If you find a different product please let me know as I would be really interested. :)

Just posted about an item in another thread which sounds like it might be suitable.

I have a 6week old and wanted somewhere high up in the kitchen to put him in whilst I was cooking etc as I hate him being low down on the floor in the bouncer chair.

I bought this:
direct.asda.com/Swivel-Feeding-Chair---Dot-to-Dot-fabric/002676298,default,pd.html.
It doesn't look very impressive there, but there's a good youtube video explanation:

A friend has an older version that doesn't have the swivel base. She's been using it for 2 years already and currently uses it for both her 2 year old and her 6 month old.

The advantages to me:
Suitable from birth
Very durable
Easy to pack up and take away with you
Converts to booster seat - longevity
Doesn't take up mounds of space- just sits on a regular chair (big advantage in a flat)
Excellent value - £30!

Hope this helps!