C4C Surveys - get the survey URL via oData

Currently for surveys in C4C we send these out via email using the #surveyNNN# placeholder.

However we have a new requirement where we'd like to put the survey link on our website. Is there any way to generate/get the ID in the survey URL so we can construct it externally, rather than as part of a workflow?

https://myxxxxxx.crm.ondemand.com/sap/ap/public/survey?id=1A1F4FD523AA6FCB1DGE5F19CBC13E7AECE7FDD5

I see there is an odata service SurveysCollection (note extra 's' on Survey, not SurveyCollection which just contains each survey design) but I can't seem to access that - even with full admin rights.