You're going about this backwards, and it does give the impression of entryism.
What's wrong with getting elected (or, more likely, just being allowed on as so few stand!) on an SBT platform, putting it into action? You'll lose all moral authority if we rise against you, you won't be able to fulfill what you stood on, and the next time your seat comes up somebody from here wopuld stand against you and there'd have to be an election. You'd lose as you'd be totally discredited.
Or... You could even get elected to the Trust board, and make it conditional on a positive result on a Sky Blue Talk referendum (how about we make the margin needed more than 52:48 though?). You could commit to resign if you didn't get that.
Or... you could commit to stand, but only if enough people here vote for you to stand before the deadline for submissions at the Trust.
All those would get you your democratic mandate from here, you could take your pick which one of those you think's appropriate for you.