Car seat abroad

[Pandora85]

Not sure where to post this but I need some help.
We go to Poland at new year and have transport from the airport to the hotel arranged (its for a family wedding and has been arranged and paid for by the bride and groom)
Weve been told that car seats are not the law in taxis and minibuses over there but we want to make sure our 3 year old is safe so are planning on getting a spare seat to take with us.
She'll need a group 1 seat (or a 1/2/3 would be best) but we expect it could be a minibus collecting us and don't know if there will just be lap belts on board.
Therefore we need a car seat that can be fitted with a lap belt. Any ideas?
We don't want expensive as we already have 2 Britax seats and this would just be a spare for 4 days!!
Any help would be great as I need to get purchasing.

Why not fly with your existing car seat? (Is it not lap belt suitable?)

We aren't sure if it is and it cost about £150 so pricey to replace. Thought it was a good idea to look at all options.

It's worth asking. Some seats can be used on the aircraft itself so you'd not need to check them, but you'll need to ask the airline to confirm their policy.

(Also if the airline does damage it they should replace it for you?)