Hi,
I'm restoring / preparing a classic Mini Cooper for circuit racing. The inner sills have lots of rectangular holes which take grommets. I don't know the exact size hole you've got to fill but Mini Spares stock this grommet to suit.
http://www.minispares.com/product/Class ... ommet.aspx 1" long by 13/16". Maybe two cut about could fit?
Alternatively a small piece of 1mm polythene sheet could plug the gap with Tigerseal or similar sealing around the edges from above and below? That would probably be a more permanent fix than a grommet.
Adam
TR7 V8 DHC Jaguar Solent Blue. 9.35cr Range Rover V8, Holley 390cfm, JWR Dual Port, 214 Cam, Lumention, Tubular Manifolds, S/S Single Pipe Exh, 3.08 Rear, 200lb Spax & PolyBushes all round, Anti- Dive, Strut-Top Roller Bearings, Capri Vented Discs & Calipers, Braided Hoses, 4 Speed Rear Cylinders, Uprated Master Cylinder & Servo, AT 14" 5 Spokes or Maestro Turbo 15" Alloys, Cruise Lights, S/S Heater Pipes, Replacement Fuel Tank. No Door Stickers. Mine since July 1986, V8 from 1991 courtesy of S&S V8 conversion and big brake kits.