These parts are very fine and need a steady hand to remove them from the base. Most all you will need a brand new, very sharp scalpel blade - plus a magnifying glass of some description to see what you are cutting.
The panel above is what Elefant recommend. Even though their English is a bit dodgy, I think it is clear enough!!
The Tamiya hull top represents the style of handle on the earlier marks of Chieftain Mk.1-3/3 and 5.
This photo represents the style of handle on the
later marks of Chieftain upated Mk.5 onwards.