Passing Parameters to MDX Shared Datasets in SSRS

So part of my ongoing work involved making some changes to a SSRS report that was running off some MDX, querying a Tabular Model. It needed Parameters to feed Shared Datasets. and the two had to talk nicely. This was not as easy at is seems. First of all big warning to anyone wanting to mix DAX and MDX on the same report: the two won't talk well to each other. So in the below examples, whilst the DAX queries to get the parameters would have been relatively easy, they ultimately had to feed an MDX query (as that was what was pre-existing). This is a problem as Member Names are not in the same syntax for DAX and MDX so you can't easily feed a selected Member from a DAX resultset into an MDX operator like STRTOMEMBER.