230v Trailing Edge Triac Dimmable T8 LED tubes

[FozzieBear]

We have 10 off double T5 fluorescent fittings in our village hall that we want to convert to dimmable LEDs. These fittings have wire cages to protect them from damage and to replace the whole fitting is not really economical for us.

We were of the understanding that we could get an electrician to remove the existing ballast/control gear and rewire the fitting and insert single ended 230v led tubes?
However when looking online for dimmable LED T5/T8 tubes they appear to require a triac dimmable constant current driver. If this is the case then it would appear that to use these tubes we require at least 10 of these constant current drivers, one installed in each fitting which involves additional work and is not what we expected.
I wonder if any sparks on this forum knows:-

1. If a 230v Triac Dimmable LED T5/T8 tube is available which works at mains voltage with a normal trailing edge triac driver; or
2. As we want all 20 tubes to dim simultaneously. Can they all be connected to a single constant current driver i.e. 10 fittings x 2 lamps per fitting x 20 watt per lamp = 400 watt so perhaps a 600 watt constant current dimmer?
3. What are the implications as far as existing wiring is concerned. Can the existing 1.5mm cables to the fittings carry 36-42 volts DC within the same enclosure as the other 240v lighting and power supplies as far as 18th Edition Regs are concerned. The route to each set of lights is in 20mm conduit with no other cables but these single core cables also run in a box trunking along the room with ring main and other 240v circuits

Any thoughts on the above would be appreciated