Unless you have heard that it is permanent it may not be an issue. This has happened several times before.
There are insufficient airframes for Oxford to keep three on-line at the two locations ..... they are far more difficult to maintain than the EC135 and for a long time the Lippitts Hill fleet were supported by a 135 for the same reason. That was regularised by the move of the Essex aircraft to Lippitts Hill and then all the fleet to North Weald.
It all underlines just how well the stand-alone maintenance organisation at Lippitts Hill operated. They knew their aircraft and repaired them on demand. Yes they were sometimes all offline [and sometimes deliberately offline] but equally they were able to put 3 145s on line for special events. That, I would venture, simply does not happen now.