What about the following situation :
A unit declares a regular flank charge
An opposing tUG comes forward intercepting it
In our case it could not avoid the flank charge as the whole flank was not protected, only partialy . But Am I right that if the intercepting unit could have moved more forward and cover the whole 1 BW x 1 BW sector covering the flank it whould cancel the "flank" effect as the validity of a charge is computed when the charge is done !
NB I did sent the picture to Nik and RJC as it is too big for here
The picture from Jacques:
(https://i.imgur.com/MwipYeo.jpg)
I think we have to repose your troops a bit as it looks to me like you have the 1BW x 1BW square in the wrong place. I am assuming that the unit about to be hit in the flank is facing down the screen despite the one base that is not quite in formation and is facing up. The square should be in line with the front rank thus:
(https://i.imgur.com/np8ANCf.jpg)
Thus if the left hand unit facing down the screen is an interceptor it cannot actually reach the position it is in touching the 1BW x 1BW square as it has moved within 1 BW of enemy chargers who I am assuming are in their starting position.
BTW I think that there is another possible issue with all of this in that I am not sure that the interceptors could even reach the charger's path of charge whilst staying 1 BW from the charger's as the path of charge stops at the point of contact if the target stands to receive the charge.
OK On my picture, the white cloak TUG is intercepting and has moved and stopped at 1 BW from the charging TUG . For the picture I placed a 1 BW square from the intercepting TUG for clarity of the picture .
Now the charguing TUG on the left hand can still contact the flank of the target TUG on the right hand . But I just wanted to be 100% sure it was still a flank charge, which it is to me as the intercepting unit does not manage to proteck the flank of the target .
But it could happen that it might cover that square next to the target ( Nik's Picture ) ?
Now I will have to learn how to reduce picture size 8)
My picture shows where the intercepting unit would have to get to (as a minimum) in order to prevent the charge counting as a flank charge. So in your case it could not be prevented as the intercepting unit would have to get closer than 1 BW to the chargers which isn't allowed.
However, as mentioned I don't actually think the interception was possible anyway.
An intercept (and, FWIW, a countercharge) must move into the Charge Path of the charging enemy.
As the target of the charge in question is standing the charge path only extends as far as the point of contact - it only continues past troops who skirmish or run away. Hence the charge path stops on the line in the following picture:
(https://i.imgur.com/KClgAxy.jpg)
Point taken