Check authority and available payment methods during preparation, while waiting for the official instruction that makes a payment appropriate.
Prepare without prepaying a later stage
Bank approvals and corporate sign-offs can take their own time, so assign responsibility in advance. Do not use that preparation as a reason to ignore the published sequence. A scheduled transfer date is a financial event, not a forecast of when vetting or immigration adjudication will finish.
Check the banking arrangements early and prepare without prepaying, since those are two different things and the distinction is what protects the applicant. Preparation means confirming limits, giving any notice a bank requires, assembling the documentation a sending institution will ask for, consolidating funds where necessary and documenting that consolidation, and establishing realistic transfer times. None of that involves sending money to anyone.
Prepayment means transferring funds ahead of an instruction, which achieves nothing procedurally and creates recovery risk. Do the first thoroughly and the second not at all. Where an adviser suggests that readiness requires funds to be placed somewhere in advance, ask precisely where, on what terms, and what the applicant's position would be if the matter did not proceed.
Where consolidation between accounts or institutions is needed, do it early and document each movement as it happens, since a transfer made hurriedly at the point of payment adds an unexplained step to a financial history that will be read closely.