Supreme court has ruled that the prorogation isn't illegal. So what a Scottish court says is irrelevant.
https://www.supremecourt.uk/cases/docs/uksc-2019-0192-summary.pdf
Extract from the summary of the judgment (pdf).
This prolonged suspension of parliamentary democracy took place in quite exceptional circumstances: the fundamental change which was due to take place in the constitution of the United Kingdom on 31 October. Parliament, and in particular the
House of Commons as the elected representatives of the people, has a right to a voice in how that change comes about. The effect upon the fundamentals of our democracy was extreme.
No justification for taking action with such an extreme effect has been put before the court. The only evidence of why it was taken is the memorandum from Nikki da Costa of 15 August. This explains why holding the Queen’s speech to open a new session of parliament on 14th October would be desirable. It does not explain why it was necessary to bring parliamentary business to a halt for five weeks before that, when the normal period necessary to prepare for the Queen’s speech is four to six days. It does not discuss the difference between prorogation and recess. It does not discuss the impact of prorogation on the special procedures for scrutinising the delegated legislation necessary to achieve an orderly withdrawal from the European Union, with or without a withdrawal agreement, on 31 October. It does not discuss what parliamentary time would be needed to secure parliamentary approval for any new withdrawal agreement, as required by section 13 of the European Union (Withdrawal) Act 2018.
The court is bound to conclude, therefore, that the decision to advise Her Majesty to prorogue parliament
was unlawful because it had the effect of frustrating or preventing the ability of parliament to carry out its constitutional functions without reasonable justification.
The next and final question, therefore, is what the legal effect of that finding is and therefore what remedies the court should grant. The court can certainly declare that the advice was unlawful. The Inner House went further and declared that any prorogation resulting from it was null and of no effect. The government argues that the Inner House could not do that because the prorogation was a “proceeding in parliament” which, under the Bill of Rights of 1688 cannot be impugned or questioned in any court. But it is quite clear that the prorogation is not a proceeding in parliament. It takes place in the House of Lords chamber in the presence of members of both houses, but it is not their decision. It is something which has been imposed upon them from outside. It is not something on which members can speak or vote. It is not the core or essential business of parliament which the Bill of Rights protects. Quite the reverse: it brings that core or essential business to an end.
This court has already concluded that the prime minister’s advice to Her Majesty was unlawful, void and of no effect. This means that the order in council to which it led was also unlawful, void and of no effect and should be quashed. This means that when the royal commissioners walked into the House of Lords it was as if they walked in with a blank sheet of paper.
The prorogation was also void and of no effect. Parliament has not been prorogued. This is the unanimous judgment of all 11 justices.
It is for parliament, and in particular the Speaker and the Lord Speaker to decide what to do next. Unless there is some parliamentary rule of which we are unaware,
they can take immediate steps to enable each house to meet as soon as possible. It is not clear to us that any step is needed from the prime minister, but if it is, the court is pleased that his counsel have told the court that he will take all necessary steps to comply with the terms of any declaration made by this court.
It follows that the advocate general’s appeal in the case of Cherry is dismissed and Mrs Miller’s appeal is allowed. The same declarations and orders should be made in each case.