Everything about Luton's existing capacities can be found by doing a Google search using the term " maximum runway rate Luton Airport"
The top of the Google list is a link to a PDF called Capacity analysis of London Luton Airport - Gov.uk
Very interesting info as it goes into details about the capacity of the runway, apron, CTA and different parts of the terminal and was no doubt used in the planning of the airport upgrade.
Conclusion
For an airport to be designated as coordinated it is a requirement of legislation that the following two issues should be established. Firstly that the shortfall in capacity is so serious that significant delays cannot be avoided and, secondly, that no short term solution is available.
This analysis concludes that the constraint to overall airport capacity caused by the individual capacities of central security and of the runway-taxiway network meets both criteria: they individually are sufficiently serious that delay would become unacceptable if inappropriately managed, and that in each case no short term solution, other than coordination, is available.