I bet it not the suspension. Fiesta’s do sqeak over speed bumps.
Ive had 5 Mk 7 fiestas and they have all done it. One of them was worse afer changing a headlight bulb so I guessing it’s something moving about under the bonnet.
The entire wishbone will need replacing if it is a bush or balljoint. Mine was clunking over rough surfaces and it cost about £130 fitted,
they are pretty bulletproof. Mines got 130,000 miles on it now and on the suspension, I’ve had that one wishbone and a drop link.
Dont ask about starter motors or clutches though due to the learners…….