Check the bath before you blame the panel
Get into the empty bath and shift your weight from side to side. A properly installed bath sits on its own frame with the feet adjusted onto the floor and, on acrylic baths, a supported base board. If it creaks, dips or rocks, the panel will never stay put because the gap it clips into keeps changing size.
Also look at the silicone line where the bath meets the wall and the floor. If that seal has split, the bath has been moving for some time. Sealing it again without stabilising the bath simply repeats the failure.
How bath panels are actually held
There are three common arrangements. Some panels sit in a plastic channel screwed to the floor, with the top edge tucked under the bath lip. Some are held by clips or magnetic catches on a timber batten frame. Some, particularly on older installs, are simply screwed through into a batten with cover caps.
Panels come loose when the floor channel has been fixed to a soft or uneven floor, when the batten has been fixed only at the ends, or when the panel has been trimmed slightly too short so it no longer grips the bath lip. Diagnosing which of the three you have takes about a minute once the panel is off.
Refitting it so it stays put
The reliable method is a timber batten frame. Fix a treated batten to the floor set back from the front edge of the bath by the thickness of the panel, screwing into joists or using suitable plugs on a solid floor, and add a short upright at each end. Cut the panel so it sits under the bath lip with a millimetre or two to spare, then fix it to the battens with screws and caps, or with turn catches if you want removable access.
Leave the panel removable if there is a trap, a waste or an isolation valve behind it. Sealing a panel in permanently is the decision people regret when a waste starts weeping and the only route to it is through the panel.
Sealing the bottom edge, or not
Opinions differ and both are defensible. A silicone bead along the floor keeps splash water out from under the bath and looks tidy, but it makes the panel awkward to remove and traps any leak out of sight. Leaving the bottom edge dry keeps access easy and lets a leak show itself early.
We usually leave the bottom edge unsealed where the panel is removable, unless the floor covering makes that look poor. What matters far more is that the top junction between the bath and the tiles is sealed properly, because that is the joint water actually reaches.
When a wobble means something more
Call someone if the bath itself moves, if the floor feels soft when you press it near the bath, if there is any staining on a ceiling below, or if there is a musty smell around the panel. Those point at a long running leak from a waste or an overflow rather than a fixing problem.
We refit panels and rebuild bath supports as small standalone jobs, and we check the waste and overflow while the panel is off, because that is the one moment when everything is visible.