Renting space in another public sector data centre complies with EU procurement rules. Further information on this is described in the guidance from Scottish Government procurement document "shared services in the Scottish public sector: impact of the eu public procurement rules" which describes the Teckal  exemption.
1. If an SG Executive Agency or non-Ministerial department which does not have separate legal identity ( i.e. which contracts in the name of "the Scottish Ministers") wishes to take space in a public sector data centre then there is no procurement obstacle to that happening as no contract can be said to be created between the same legal entity ( i.e. Scottish Ministers).
2. For organisations that have a separate legal status they can enter into a formal SLA as long as the SLA does not provide a recourse to the courts to resolve disputes. T he payment charged should only relate to the recovery of full costs and must not include any element of profit.
In summary the arrangement is an agreement between public sector partners which sets out what they can expect from each other in colocating in a data centre. It is not a legal contract but it does set service levels to ensure there is a clear expectation and understanding of the partnership.