Manchester (MMSI as was) is a bit erratic when it comes to retrieving drawings. Their website has gone through so many changes over the last 7 years that it's virtually impossible to find what you want because the website is geared towards the general public, i.e. content-heavy, yet knowledge-lite.
When I was trying to help Graham Nicholas with his kit design for the ex-Great Central "B7" 4-6-0, Manchester were able to find the full-fat GA on request. I think they charged me about £80 for a digital copy.
I knew also that they had a similar drawing for the "B3" 4-6-0 because it had been published in a book about Great Central locomotives but, when I requested a copy, they were unable to find the drawing. Likewise, they also have a drawing for the GNR(I) S2 4-4-0, but they were unable to find that one as well - strange, given that it was previously available via their archive website.