UK Identify perimeter Dado Trunking

[AlphaElectrical]

Costing up a job for a new client, they want to extend some existing galv dado trunking. Does anyone recognise the manufacturer of this trunking system (150mm x 75mm):

 

[ipf]

That's basic galv trunking not dado. Looks like 4x2''
I reckon the switch has been adapted and looks iffy to me. What back box is involved?

 

[ipf]

Edit the above. 6x3'' I see.

Try 'Trench'. They do flat lid trunking with adaptations for backboxes.
I suppose it could be adapted as dado.