Let's picture the following scenario: There are two supermarkets that carry the products you need. But you have a preference and you really want to buy from supermarket A. Now you go there and tell them "here is a list of products we need to buy. We need you to complete this paperwork, stating all the article prices in our local currency. You also must attach (as opposed to: please also attach) a copy of your trade certificate and a CV of your managing director as well as the lady on the cashier. We will then award the contract to you". Total nonsense you say? Fully agree, but this is really what we have to put up with sometimes. The excuse is usually that it is required by law to proceed like that. Fine, all that means is that the law is wrong and needs to be changed.
If you have two training organisations in the world (a third one being on hold due to temporary admin issues), offering exactly what you need and are required to book because of ICAO requirements, there is only ONE procedure to be followed: Ask if there are places available and if so, book by going through the admission process of the service provider. Period.