Decide before instructing anyone. Shared work, the purchase, the corporate structure, the business plan, can be split by agreement; each partner's own eligibility review, evidence preparation, and family filings belong to that partner. Put the allocation in writing, including who pays if one partner withdraws. Government charges and professional fees are separate from the invested capital in every case.
Watch for a conflict between the partners' interests
The two partners' interests diverge more often than they expect, particularly over control terms, which one party may need more than the other. Ask any adviser to say plainly whom they act for and to give an itemized scope. Confirm current official fees at the time each step arises rather than budgeting from an old figure, and resist spending simply to reach an amount someone has promoted as a threshold.
Add one further protection for both partners: agree in writing, before anyone is instructed, what happens to shared work if the two cases diverge. Where one partner's position is straightforward and the other's raises a question, the shared items — the business plan, the corporate structure, the valuation — may need revisiting for reasons that benefit one partner more than the other, and the cost of that revision has to fall somewhere. Decide in advance whether it is shared, borne by the partner whose facts caused it, or triggers a renegotiation.
Hypothetical example: two buyers of a computer repair chain agree a simple rule at the outset — shared work is split evenly, and any rework arising from one partner's individual circumstances is that partner's cost — which takes ten minutes to agree and prevents a dispute at the point when both are already under pressure.