It's a Policy Guidance Note, so you may well find yourself asking your legal advisors: "what if I decide to ignore the Guidance?" or, getting into the detail, "Does this only apply 'above the threshold'?" - actually I understood that the Principles of the EU applied regardless of the threshold anyway.
Of course all these initiatives are dependent on whether those who view themselves as being 'victims' have the appetite to pursue a case through the courts. Surely, anyone who has considered themselves wrongfully discriminated against in a procurement process during the boycotts up to now would have already taken a case - nothing has changed as this is only Guidance.
Regardless of all that, it may have been interesting to establish what the actual impact of the boycotts to date have been, for example, has a procurement decision actually been different in terms of its award outcome? If there was no change in a real life procurement decisions, then the boycotts could only have had 'political impact' in raising awareness of the issues - something which the anticipation and implementation of the new Guidance has paradoxically probably been more effective in doing.
Anyway, here's the key statement from the Guidance for anyone who has a interest in political procurement:
Public procurement should never be used as a tool to boycott tenders from suppliers based in other countries, except where formal legal sanctions, embargoes and restrictions have been put in place by the UK Government. There are wider national and international consequences from imposing such local level boycotts. They can damage integration and community cohesion within the United Kingdom, hinder Britain’s export trade, and harm foreign relations to the detriment of Britain’s economic and international security. As highlighted earlier, it can also be unlawful and lead to severe penalties against the contracting authority and the Government.I suppose you could also interpret this loosely as: "Public procurement can be used as a tool to boycott tenders from suppliers based in other countries if the UK Government decides it wants to, but that choice cannot be devolved to any lower level of government".