How many variations can be attempted?: variations affecting the different items of property
The published advice (IHTM35081) is that variations covering a number of items should be made in one instrument. However, as explained at IHTM35011, the focus in IHTA84/S142(1) is on the redirection of items of property in the estate. Accordingly, in any particular estate, there can be as many instruments of variation as there are items of property.
In particular, there appears to be nothing to stop a series of instruments each selecting an item of property subject to the same residuary gift and redistributing it. The only prohibition is on purporting to redirect the same item, or part of it, more than once. (IHTM35082)