Scimitar F1

Hi From my username some will realise that railway modelling is not my usual thing. However growing up in Ealing close to the Western region mainline out of Paddington I loved the Class 31s, 50s, 47s and 52s of my youth. I have no inclination to make and operate a layout as I am really a scale modeller and do not have time to make a layout that would meet my desired level of detail. What I would like are static models of these prototypes and the question is what is the best way. The Heljan locos are excellent value and most are now pretty accurate. Is there a way of getting the bits without the motors and electrics more cheaply than buying the ready-to-run loco? It seems such a shame for the motors etc. to sit unused on the display shelf. I would also repaint the body so the painting would be wasted too. Any help would be much appreciated. Will