I think that grid upgrades are the only good solution here (and those are already happening), because shifting enough consumption towards where the windfarms are strikes me as ridiculous (what fraction of London is going to migrate to Glasgow once electricity is 40% cheaper there, honestly?) and just luring a handful of new datacenters to Scotland (with cheaper electricity) is not gonna cut it.
Demand-side anything (or even storage) is not gonna solve this either, because the british north/south grid connections are already close to the limit most of the time; this is not just a peak-power problem.
There are very similar problems in Germany (insufficient north/south grid connectivity), and expected long-term costs (within 2037/2045) are in the €200b range (roughly half is for off-shore connections):
https://www.netzentwicklungsplan.de/sites/default/files/2023... (take with a grain of salt because this is material from the grid operators, not some neutral source).