Yes.
No Tacho= It ain't leaving the UK
https://www.gov.uk/drivers-hours/passenger-carrying-vehicles
We had to cancel a Scout trip at Easter to Luxembourg for exactly this reason at very short notice.
There is a reason why minibuses are common in the UK and as rare as hens teeth in the rest of Europe.
The rest of Europe regards a minibus as a small bus, they are only driven by professional drivers
The local school, church, scout group, football club etc. does not own its own mini bus, they hire in with a driver when required.
To drive a minibus (>9 seats) in Europe you need the following:
Drivers with D1 Licences, or who passed their test before 1997 (This 'grandfather' law will be repealed in the near future, but you are OK for now)
or a driver with a PSV licence
The licence needs to the modern credit card type with a photo
The vehicle needs to be fitted with a tacho suitable for the age of the vehicle (which means in reality the old paper disc ones could be an issue if there was an accident, they have been phased out in the rest of Europe but they are not yet illegal in the UK)
The drivers each need their own tacho card, this is a process that takes 3 weeks to obtain
The vehicle needs two warning triangles, spare bulbs, two breathalyser kits (buy on line, a lot cheaper than buying in a shop) plus a hi-vis jacket for every person on board, plus working seatbelts