I've been trying to find a source, hopefully in the UK, for simple bar type cable clamps. This is like you used to get in UK 3 pin mains plugs, a small strip of fibre board with 2 holes at about 17mm centres. We've been using the clamp from a multi-way connector, it was cost effective to throw the rest of the connector away, but they've changed the design to a metal clamp.
You would think that someone is making these by the bucket load, does anyone know who? The only company I found that had been making them had stopped & scrapped the tooling.