Do you want to set out your vision of the future for UK outside of the EU. .... I don't mean vague references to "sovereignty, control over borders, etc.
Which are important issues, however.....
I mean real specific issues like how we'll cooperate with EU on sanctions to rogues states
How about the same way in which various nations already come to agreements about such sanctions, either by direct talks with each other or via the United Nations, NATO, etc?
how we'll replace our current trade with EU
As we've already debated at length, it will not all need replacing, since the U.K. would continue to trade with EU nations. The country could work to increase trade with non-EU countries in exactly the same way that it did before being in the EEC/EC/EU.
how we'll manage when Scotland and Wales have separated from UK
Isn't that a somewhat different issue? Even so, it has happened before when the Irish Free State was formed.
how the expats in EU will be treated, what will happen to all the EU nationals currently in UK
The only fair thing to do there is to agree that those who are already resident (whichever way around) will remain as legal residents.
What will happen to all the current EU legislation in UK,
I would hope that within a short time much of it would be repealed.
how will we cope with land borders between Eire, Scotland and Wales
Presumably EU withdrawal would take place before Scotland might get around to voting for independence, so as it would still be part of the U.K. nothing would change there. Wales ditto, if it even considered independence.
As for the Republic of Ireland, there have been open borders between it and the U.K. since long before either joined the EEC in 1973, so would anything need to change?
how will OCTs be affected
Perhaps the citizens of those might end up being treated better by H. M. Government.
how will currency exchanges be conducted
As the pound Sterling isn't used as official currency anywhere else in the EU, why not exactly the same as at present? I don't see why anything would need to change at all.
how will financial processes be managed
What financial processes, specifically?
how will the mass replacement of passports be processed,
Would they bother with a mass replacement? They could simply reintroduce a U.K. passport and start issuing it as existing EU passports expire. Or perhaps offer immediate replacement for those who would like to be rid of their EU passports as soon as possible. Ditto for driving licenses and being rid of the EU emblem on them.