Thank you very much for the replies.

I was thinking of wedging something into that channel and cable ties with the ends cut off sounds good.

I have many sizes at home so I'll give it a go and be careful and see what happens.

If for some reason I'm not successful I'll post back here.

Thanks again everyone. This forum is so great and helpful.

Theatre Room: Sony 4K VW500ES, 861v8+ID41, HD621, DSP6000's, DSP5000C, DSP5000's, Oppo 205, Sat STB, XBox One X, Stewart Cinemascope Screen, QNAP TVS 1271U-RP (96TB) with Sooloos/Roon core pkg.