Let's clear this up.....
First, the four power cars initially repainted into green (43005/041/187/188) were not modified with traction/brake interlock when they were painted because the sliding door project was not authorised at the time, so the power cars to be fitted were not known.
Second, three of the four initial green power cars (43041/187/188) were modified with the interlock at Landore, so do not need to go to Wabtec. Landore has historically been used by GW, back from BR days, for this sort of mod programme - for example, Landore did most of the ATP fits to power cars. Obviously Landore is now shut, but 43005 still needs to be converted, hence the move to Wabtec. Quite why GWR didn't get Landore to modify 43005 before it closed is a question for GWR.
Third, GWR power cars so far modified with the interlock are 43004/016/040-042/092/093/098/153/154/170/186-189/194/198. This leaves 43005/094/097/122/155/158/192 to be done, of which 43005/094 are at Doncaster.