It seems like that pie has about 15 stocks and about 15-20 GBP total value, is that right?
Doing a manual rebalance on such a pie when thereās 1 GBP min. order value does not make much sense.
As Dougal1984 mentioned, you will end up with the excess money from the sold shares sitting in the cash pile. You will not lose it.
I would rather ārebalanceā the pie by investing a bit more funds into it and use the self-balancing distribution to achieve (or at least get closer to) the target % allocation.
Why not just rebalance when you put more in? When you buy stocks in a pie, the minimum pie investment if you have 100 stocks and one stock requires a minimum investment of Ā£1 is Ā£100.
The same you could argue in reverse, to best rebalance a pie with no new funds for a new holding added, is you need to sell the minimum lot size and purchase the new stock.
Ideally you want to rebalance your portfolio as little as possible. That way you avoid market fees and bid/ask spread and any other fees like FX charges.