Alternative classic looking cable bundle sleeves

I'm updating and extending the existing cable loom of my 65' Volvo Duett (adding overdrive, rear fog light, relay for headlamp main supply etc.). The original sleeves are made of a rubber/plastic material that was slightly shirked around the bundles. So impossible to replace or add cables.
Anybody an idea of a good alternative prefarable splitable so you can sleeve also existing bundles with connectors on the ends. I recon the ribble plastic ones as too modern and the self bonding tape is also not my favourite.

Thanks!

Thom