Keep three ledgers: the purchase price and business spending, transaction expenses such as broker, accounting and business legal work, and the cost of preparing the visa case itself. Treatment of professional fees varies with what the work actually was, so have the invoices reviewed rather than assuming a single rule applies. Fix the order of spending as well as its categories. Due diligence comes before the offer, the offer before the funding transfers, the transfers before the application; money spent out of that order tends to be spent twice. Ask each adviser what has to be settled before their own work can start.
Ask what each fee actually bought
Invoices that simply say "professional services" invite questions. Ask advisors to describe the work — due diligence on the target, drafting the purchase agreement, valuation, or preparing the application — because that description drives how the spending is characterized. Government charges should be confirmed as current at the step where they arise.
No budget buys an approval, and immigration approval does not guarantee recovery of an excessive purchase price. One expense deserves its own line: the cost of walking away. A refundable deposit, a break fee or a due-diligence budget spent on a target you decline is the price of not committing capital to an enterprise the evidence could not support.
Compare it against the premium in dispute, and the arithmetic of the decision usually becomes clear.