Hi,
I've built (and since sold) a class 15 from this supplier, the kit went together very well, the whitemetal castings were over sized and not as good as you would expect in todays market, they did however fit together and only moderate shaping was required.
This looks like a moment where you make the parts yourself, which defeats the whole idea of buying a kit, if only MMP had a more extensive range..
I wish you well with this 'project'
M51625