Talking of chopping and hacking, I'm up to six variants using Parkside's kits (this should probably be posted on Kitbuilding and Scratchbuilding...) ie: - LNER riveted as built, LNER underframe re-bodied 6-panel, LNER underframe re-bodied 3-panel, 6-panel as built, 3-panel vacuum fitted and 3-panel unfitted...and there are still more variants to do by the looks of it. I've included photos of five of these awaiting completion and weathering.
Parkside have been extremely helpful in selling specific sprues from their kits to enable this.
In all cases Paul's definitive website is a mine of information.
The close clearances are just as difficult with the kits - there is often less than 1mm between the hopper bases and 00 gauge wheelsets. I have used Alan Gibson wheels and the way round it is to ensure the wheels are gauged in the centre of the axles, the wheels run true, ensure no wobbly wheel rims and any moulding pips from the plastic wheel centres are removed.
Hornby's model is superb and hopefully the start of a line of more variants. All that I would do to it is add the brake cross shaft, handrails across the end stanchions and replace the wheelsets.