AIP ENR 1.1.4.7
7 Civilian Formation Flights - ATC Procedures
7.1 General
7.1.1 ATC will consider formations to be a single unit for separation purposes provided that:
(a) The formation elements are contained within 1 nm laterally and longitudinally, and at the same level. Within Class F and G Airspace and subject to ATC approval, these limits may be increased to 3 nm and/or up to 1000 ft vertically.
(b) The formation, although operating outside the parameters above, has NSF approval.
7.1.2 The formation leader is responsible for ensuring safe separation between aircraft comprising the formation.
7.1.3 In making initial contact with the ATC unit, the formation leader shall clearly state the number of aircraft in the formation.
7.1.4 Where a flight plan is required, the identification of the formation leader and the number of aircraft in the formation must be shown.
7.1.5 All ATC instructions and clearances will be addressed to the leader.
7.2 Controlled Airspace
7.2.1 VFR formation flights by civilian aircraft transiting CTA/CTR/TMA are subject to the normal airspace requirements as detailed at ENR 1.4. All other civilian formation flights in Controlled Airspace are subject to NSF approval.
7.2.2 Formations in Controlled Airspace shall be contained within 1 nm laterally and longitudinally and at the same level. Where this is not possible, the formation must be split into individual elements before entering Controlled Airspace. In the event that aircraft within the formation are unable to maintain within these parameters, the formation leader must immediately inform ATC.
7.2.3 Prior to entering Controlled Airspace, the formation leader shall confirm that all aircraft within the formation are within 1 nm
laterally and longitudinally, and if in level flight, are at the same level.
7.2.4 When a formation has been cleared to climb or descend in Controlled Airspace, the formation leader shall confirm that all elements have reached the new assigned level.
7.2.5 All aircraft in the formation are to monitor the relevant ATC frequency.
As far as the UK is concerned you are perhaps pushing the boundaries of what is considered to be a formation with one hour spacing between first and last!
Re 7.1.4... try
here and
here.