Should we budget extra staff tips when our wedding bill already includes a service charge?

The catering bill for our wedding in England is £4,800 plus a 12.5% service charge: another £600. A friend asked whether we'd also prepared cash envelopes for the serving team.

The venue coordinator says the service charge is shared among workers. We haven't asked how that includes the temporary staff working our event. My partner thinks another tip would mean paying twice. I don't want to assume the £600 reaches everyone in the way we're picturing.

The government's [statutory tipping code](https://www.gov.uk/government/publications/distributing-tips-fairly-statutory-code-of-practice/code-of-practice-on-fair-and-transparent-distribution-of-tips-html-version) covers fair distribution of qualifying tips and service charges, including consideration of eligible agency workers. It doesn't mean every worker necessarily receives the same share.

We can afford a modest additional thank-you, but we haven't chosen one. What is useful to ask the venue before we decide, without requesting individual employees' pay details or treating a friend's preferred tipping routine as a rule?