As the Pis are both in cases I've placed a blob of bluetak and a chopped credit card under the slot and it seems to be doing the trick (mostly) - I wonder if some solder along the pins of the SD card might be more effective?
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.