bulkhead grommet

When I bought my 110 the previous owner had put a new galv chassis and bulkhead on.
For whatever reason, one which I can not think of he hasn't put any grommets in the bulkhead. He has run all the wires etc and everything is connected.

I am wanting to know if the grommets can be put in with all the wires in place?
Am I able to cut into the grommet and slide it over. Will the stay in?

It looks a big job to undo everything to pass them through the grommet.

Thanks

I would say thats fine.

You can get grommet strip to protect cables going through panels (like this http://www.cabletiesandmore.com/Molded-grommet-strips.php) but they don't form a good water seal. Best bet would be to get the correct grommet, cut one side as you mentioned and fit it. if it looks like it may pop out again use some RTV to hold it in place (and also improve the sealing)

Cut the grommet, feed it into the hole around the wires, small blob of sealant, job's a good 'un ..

It seemed the most appropriate thing to do. Thanks for confirming that its the way forward.