There is a bit of variation from country to country. Might be a good idea to post in the ATC section. The respondents there will give good feedback.
Remember:
1. If in doubt ask ATC (if you can).
2. Default to what's safe. If ATC aren't speaking to you and there is a compelling reason to descend with the GS (and no compelling reason not to) then just do it and tell them when you can. Pragmatic safety is always better than pedantic principle.