I have FD30 solid core fire doors, and have used proper drop down seals for the door to floor seal. These work well, especially since I have a continuous wooden floor between both rooms and landing I don't want to interrupt with thresholds.
For perimeter seals Rod Gervais recommends GM type-k trunk rubber, but I've never been able to find this in the UK.
At the moment I have Lorient Batwing seals around the perimeter which are ok but not ideal. My recent ventilation install has revealed they are not completely airtight

They are not heavy duty seals though, so one would not expect heavy duty performance. Has anyone found anything better, perhaps more akin to the seal recommended by Rod Gervais?
Cheers!
Jennifer