Flights to Aylesbury

Some of you appear interested in the drama at Lock 12 on the Aylesbury Arm of the Grand Union canal.
The story so far.....
About six months ago the wall collapsed due to erosion of the soil behind the wall.  This occurred because the stonework  leaked and water washed back and forth between the bricks each time the lock was used.To my knowledge this situation had existed for eight years and BW was aware of the condition and risks but chose not to repair the wall or take any other preventative measures.
The wall collapse occurred just before the boating season and C&RT had to lift out 24 boats that were trapped in the basin and put them back into the canal at Willowbridge, near Milton Keynes.
We have winter moorings booked in Aylesbury starting November 1. The repair date was moved from August to the end of October with C&RT offering a return lift out next week.  This we could not make and intended to cruise down the arm when it reopens.
However we have just leaned that C&RT are no longer promising the completion of repairs by the end of October so it looks like we will be flying into Aylesbury courtesy of C&RT.
How much would it have cost eight years ago to repoint the lock wall?
I am only a grumpy old boater but BW/C&RT are experienced at the management of waterways so I presumably lifting boats out and into the canal and repairing a collapsed wall after negotiating access to the lock across private land  and keeping four men on security duty for six months is more cost effective.