Überchild car seat - safety?

[Londonmamabychance]

Someone gave handed us down their Überchild infant car seat for the baby we're expecting. Will only really be needing the seat to take the baby home from hospital, as we donøt drive and normnally rely on public transport, so I am reluctant to spend money on a new one. However, I can't find hardly any information about the car seat or even the bran online, and am getting anxious if it's safe. It's one you fix with the seatbelt, which is what we'd need anyway, as it's for a taxi journey, so Isofix is not an option.

Do any of you know Überchild car seats or buggies or anything and know if they're considered safe?