Very annoying rattly thing

I've got an old Selmer 100 watt PA head that I'm using as a bass amp. Was originally EL34's but I've now converted it to take 6l6's. Selmer put an L-shaped piece of aluminium sheet behind the power valves in their amps .... no idea why, but if anyone can illuminate why, it would be much appreciated.

Problem is that as the 6l6 bottles are wider diameter, they rattle off the metal plate. I've "bent" it away as far as possible but at some bass frequencies it still rattles very loudly! Appart from just being very annoying, I'm worried that it will damage the valves. Can I simply remove it (the Output transformer is behind it) or if i do will will create some kind of weird output transformer valve induction coupling and blow up the planet?

Not sure, I've never removed one from a 'running' amp. That old one I've converted into a valve tester had the plate missing and the amp was indeed unstable when it was cranked up though - but I don't know if there was another cause since I never tried to fix it before I took it apart.

It will also act as a heat shield to prevent the inside of the amp heating up.

Hiwatt also used this strategy to protect the can caps.

I've never removed this from a Selmer so can't comment on whether it's a good idea or not.

Thanks very much chaps.

looks like it may be not a good idea to remove it, or a leap into the unknown at best. However, there's room move it a little, so I think that's what I'll do. Unfortunately it's rivited to the chassis so I'll need to drill it out :(.

Thanks again for your help.