OK, you need to stick with 1401/1405 for now since you have install issue with 1406. The install issue with 1406 need to be root caused separately. Could help if you can share the logs under c:\windows\inf folder after you installed 1406.
With generic driver, you will not get LE support on Win7. We should be able to share some scripts for additional log collection. Hope you can support. Quickly, do you happen to have any other HID device (LE or classic) and check if the issue is device specific or not.
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Disclaimer: Not speaking for my employer