Do I need a survey before fire stopping?

It depends what you already hold.

Example one. Your fire risk assessor has written "pipes in riser 3 unsealed, ceiling void over first floor corridor open to stair". That names two places. We can go to those, count the pipes, measure the void and price it. No survey.

Example two. A 1990s block of 24 flats. The assessor says "compartmentation not verified". That names nothing. Every flat wall, every riser and every ceiling void is a possible gap, and until somebody lifts the tiles with a torch nobody knows if it is ten seals or two hundred. A price now would be a guess, and guesses turn into variations.

So for the second case we start with a compartmentation survey.

We keep the survey and the sealing as separate jobs. The list belongs to you, so if another contractor will do the sealing, hand it over.