I used to travel to Elstree on a regular basis and found the Luton guys very helpful when transiting overhead.
Don't think that will change if the Lars has gone... the corridor is still published and it is in their interests to know who you are and your intentions.
Surely this is why the RAF offer the service, mainly for the protection of their birds than us grunts trucking around!
For that reason I think that the withdrawal of the service is a retro-step.