I started doing the same modification to the bogies, but found - as you've noted - that it can cause problems. For some reason, most units are fine, but one in particular (my Regional Railways 'Express' one) seems to be particularly bad. The bogies on the non-powered car both seem very keen to let the axles drop out, and the ones on the power bogie seem equally keen to flex, which occasionally causes running issues. 

I can't remember off the top of my head whether I did the full mod to all of them or whether I left some with the inner end web still in place (it's slightly less visible at least). Incidentally, once you've removed the end frame, you might as well remove the bit that goes over the axle as well, as it does nothing - obviously don't remove it from bogies which still need a coupling attaching though!

Since fiddling this I’m now moving to just having a Realtrack 156. I’ll never make a Lima example as good.
 

Also my new policy of having less models, but of high standards and quality At £200-400 quid for a 2 car DMU I only buy those that actually run in my geographic area of interest and time period. It’s a good policy to keep spending reasonable and affordable!

I just don’t seem to have much time for modelling with all that goes on at work and outside of work. Suppose an issue many people suffer from time demands and priorities? 

In further reflection, despite the Realtrack Class 156 been a very good model. The lack spares support now and long term is a bit off putting. So hence tinkering with Lima / Hornby Class 156 again. 
 

Really the bogies need replacing with Bachmann Class 150 bogies. If only Bachmann would offer these in a twin pack for £12.50 for dummy BT38 bogies rather than £12.50 each.…