Renumbering pre-1931

[truffy]

I have what I think is a pretty straightforward, if not simplistic, question.

 

I want to renumber a Hornby Schools class ('Charterhouse') from its pre-1931 guise to late 30s. Currently, it's given as E903. So, from 1931 it would have been 903. But is that simply a case of removing or painting over the 'E' on the tender and cab side-plate, or would the lettering and numbering have been redone to tighten the gap that was left?

 

In terms of removing the lettering, I think that it's printed rather than decal. What is the best approach to this? And, if painting over, does anyone have a good colour match? I would assume that Humbrol's Maunsell Green Matt (AB2410) would be appropriate for a Hornby model...but you know what they say about 'assume'!