Oh dear and after TfL wrote this is their recent Board Papers. Note the section I've put in bold type. That's a rare admission from TfL that they've cocked up some of the installations (no pun intended )
Bus driver toilets
We are almost half way to implementing our £6m programme to ensure 42 top-priority bus routes have a toilet at one end. We passed the 20 mark at the end of December and remain on course to introduce the rest by the end of this July. This is subject to successfully agreeing locations with boroughs and stakeholders. While we have tried to ensure that we liaise with boroughs and stakeholders, we are aware that some have been missed. We have flagged this with our project team to ensure this does not happen again. These facilities support a safe and efficient bus network by providing driver conveniences in the right locations. The sites and order of introduction has been jointly agreed by the principal drivers’ union Unite, our operators and us to ensure we get the most out of the investment. We have completed detailed surveys for the entire plan and continue to liaise with boroughs, private landowners and stakeholders to achieve this. Ultimately, our aim is for any temporary facilities required in the initial programme to be made permanent by April 2020.