Chickehouse
What an utterly stupid situation......to ground an airliner for 20 hours or so just for a radio LRU change....... The lunatics are clearly in charge of tha asylum !
Just for clarity in the UK the paperwork requires for a radio LRU change is just the tech log entry ( the paperwork system will route the record of the change into the log books or the equivalent record system).
So in Germany a light aircraft can be grounded for six weeks ( 20 hours for an airliner) but in the UK the same radio LRU change would result in the aircraft released for service as soon has the B2 engineer as compleated the tech log entry ( about ten min at the most).
It would seem to me that removing the D from the side of your aircraft and replacing it with a G would be something that would save you a lot of time trouble and money.