It'd be a simple job to replace a No5 charger bridge although the bridge was never available as a separate part from Ordnance (oh no it wasn't......). Just knock out the old one from below and insert your new found second hand one, Then tig weld at the side as per the EMER. While we didn't replace them, we removed, cleaned up and re-welded hundreds of loose ones.

On the other hand, if it's just got a hole in it, just slightly countersink it and get it mig or tig welded up