stamp duty higher rates for additional properties question

[glider26]

Hi, here's a question regarding the higher 3% rate. Bear with me with me while I set the scene.

We are a married couple with kids and are selling our one and only home. We exchanged late last year and will complete in 5 weeks. We have not found somewhere else yet. We will probably move into rented. As we wish own a buy-to-let flat anyway in the future, we are considering the following option: we buy a modest flat more or less immediately, move into it, and once we find our long term (significantly more expensive) property we move into that and rent out the flat. All cash, no mortgage.

Is there a way around paying the higher stamp duty rate on our long term home, even though it will be our second property at the time when we buy it? Say if we agreed to pay the higher rate on the flat even though we technically don't need to as we are moving from our current home into it? Thanks.