If you push on to Delta you block it.
Nowhere else in Europe insists on the Hectopascal read back and American crews fly to Europe.
The auto frequency change is not difficult. Some of the largest airports in Europe use it very effectively to cut out unnecessary chat. If it’s not appropriate for some reason the controller simply says “remain on this frequency until instructed, clear take off.” Another option is simply “Contact departures” or “contact ground” without the verbiage of a frequency.
Luton needs a real operational kick in the backside to sharpen up the whole operation.
LTN Man. You have summed up the problem with Ltn very aptly when referring to the fact that roads and car parks get priority over a dead end East apron that is going to cause taxi delays for probably decades. The whole car parking & drop off area has been dug up several times and losing another 30-40m to create a free flowing apron would have been insignificant in the grand plan.