The UKs Obligation to Obey EU economic rules

All EU countries are in the stability & Growth pact but the UK is not in the Euro-Plus pact.
“The UK is not a member of the single currency and cannot face sanctions under the EU’s Stability & Growth Pact. The UK’s obligation under the SGP is to “endeavour to avoid an excessive government deficit” as a result of its Protocol to the EU Treaties (Protocol 15). ” – H.M. Treasury 2015
Paragraph 4 of Treaty Protocol No 15, exempts UK from the obligation in Article 126(1+9+11) of the Treaty on the Functioning of the European Union to avoid excessive general government deficits, for as long as the state opts not to adopt the euro. Paragraph 5 of the same protocol however still provides that the “UK shall endeavour to avoid an excessive government deficit”. On one hand, this means that the Commission and Council still approach the UK with EDP recommendations whenever excessive deficits are found but on the other hand, they legally can not launch any sanctions against the UK if they do not comply with the recommendations. Due to its special exemption, the UK also did not incorporate the additional MTO adjustment rules introduced by the 2005 SGP reform and six-pack reform. Instead, the UK defined their own budget concept, which was operated by a “Golden rule” and “Sustainable investment rule” throughout 1998-2008 and since then by a “temporary operating rule”.
The UK fiscal debt-ratio target under the “temporary operating rule”, also differs from the SGP debt-ratio target, as it measure compliance with the target according to “net debt” rather than “gross debt”, and only require a declining trend to start from 2015–16.
Despite claims that The SNP were advocating a ‘spend, spend, spend’ policy the economic proposals in their general Election Manifesto conformed with the above