If Aquasabi haven’t got it then you will struggle I’m afraid. They are probably the largest ADA seller in Europe.
There are not that many true distributors of ADA in Europe so all shops are sourcing from these distributors.
It is tricky for shops to source the ADA tissue culture plants as they are in limited supply. The little that is available Aquasabi snuffle most. I would suggest if they say it’s unavailable, it really is, if that makes sense!
You may be lucky and find a random ebay seller that has it, but personally I’d not be 100% convinced they are genuine.