Jackonicko,
You misread me. Of course FCAS will be a system with several component parts, that is plainly obvious. But the core platform will be a manned fighter/strike aircraft, that is the node of the airborne system and that is where the industry focus is. Air Vice Marshal Rochelle was quoted as saying of FCAS says: “It’s a platform within a systems of systems which is important in the future... There’s always a system within a system. The question for us is: how far do we go further forward in the conceptual ideas and what is the next natural evolution of those concepts?”. Whatever the Tempest mockup eventually emerges at will be with platform around which FCAS will sit.
As Gavin Williamson said "Team Tempest's activities will span work across 50-60 national demonstrations, covering aspects such as low-observability, advanced sensors, propulsion and future cockpit design, contained within an existing FCAS technology initiative." That's a lot of R&D work and they can't do everything, so it makes sense to bring in smaller partners for particular demonstrator models. I agree it makes sense for Team Tempest to have an oversight of all the technical aspects.
FCAS started in 2011 to identify and research unmanned technologies. In 2014 under the Lancaster House talks it became an Anglo-French programme, the government allocating £120M of its £200M unmanned research budget for the joint study phase designed to build on experience with Taranis and Neuron (£80M also went to further work on both). In March 2016 £1.54 billion was committed to a full scale demonstrator programme due to start at the end of 2017, with a first flight planned for 2025 and an operational system during the 2030s. But the full scale demonstrator never happened for whatever reason and Dassault by early 2018 were looking at Airbus' fighter programme instead.
It seems to me to be no coincidence that as France and Germany began studying a manned Eurofighter/Rafale replacement for the 2040s and BAE Systems began to look at its diminishing production line at Warton, that suddenly FCAS stopped being a purely unmanned technology demonstrator but has grown to encompass a manned Eurofighter replacement as well, including technologies required for future cockpits etc. FCAS has now also absorbed Rolls-Royce's future engine work which their chief engineer for future defence programmes Conrad Banks in Februrary 2018 stated was for futuristic programmes in general rather than FCAS-specific work.
In March 2018 Team Tempest was formed to look into FCAS concept, some 7 years after FCAS began, indicating whatever original concepts there were have been reviewed and revised. In July Flightglobal revealed BAE Systems had received a single-source award with 12 month contract for unspecified FCAS work, we can only conjecture what that might be.
FCAS still seems quite undefined, or at least everyone is holding their cards to their chest. Its clear that as it has evolved FCAS has had various national and multinational threads. If the UK does join one of the European programmes on offer its highly likely that the scope of FCAS will change again.