I don't know the legal opinion, but I would say hold off.
What
if he dipped into the savings to the tune of £4k and spent it on something
he wanted?
A new kitchen isn't a need or necessity, its a 'would
be quite nice'.
If he agreed that it would add value to the home
and that you'd both benefit from the increased equity, then thats a
different matter.
Usually once
separation has occurred, all
joint accounts should be put into 'Marital Dispute' to prevent either
parties spending before finances have been agreed.
WR