This article comes from Lee Orphan in Sumner, WA, USA:

Additional MGA Storage

If you are planning to travel any distance in an MGA you quickly discover that storage for any kind of luggage is at a premium considering the spare wheel and miscellaneous parts that one carries in case of the inevitable break down. One possible solution for those who have switched to a single 12 volt battery is to use the second battery tray as storage of those necessary repair parts. However, the MGA battery tray is exposed to the elements.

The solution to this is simple, create a shelf system for some form of container. While the solution below may seem McGyverish to some, it works. I’ve tested mine for over two years now and have had no problems. The difficulty was finding a properly sized Tupperware like container with an air tight seal. The first picture illustrates what the unit will look like installed, and the second illustrates the wooden parts that you will use.

Needed materials:
½ plywood, 2½ x ¼ inch elevator screws or carriage bolts (2 pcs), 3 ft of 1-inch nylon web, end snaps, and a 29 cup SnapWare Mods container. It is important to get this particular model of container as it measures 6x10x8 inches, has an airtight seal and fits in the battery box area. They are available through many online sources such as Amazon.com or organize.com.
The Build Process:
First, cut a fill block for the battery tray frame and a shelf for your container to sit on out of ½ inch plywood. It should measure approximately 6-3/4 x 8 x 1-1/2 inches (three layers of ½ inch plywood glued together). Remember to measure your own battery tray as there are wide variances in measurements. Next comes the shelf. The measurements here are approximately 6 3/4 x 13 x 1/2 inches. I personally like to make a stop at the end of the tray, but that is optional.

Make a holding strap out of a scrap piece of metal that covers the bottom (if you don’t have any, use 1 inch steel that you can get at any home center). I like to put an additional inch up around the sides to prevent any side movement, but that is personal choice. Drill two holes in the strap where the elevator screws will drop through.

Once you have cleared the sawdust and put your saws away, place the fill block in the battery frame tray and the shelf over it. After squaring up the two pieces of wood, take a screw or nail to bind the two together. Feel free to use a little glue or adhesive if you want, Gorilla glue works well if you have some.

Temporarily put something heavy on the shelf to help with the next step. From the bottom side, place your retention strap where you want it to be located and mark the drill locations on the bottom of the boards.

Pull the boards out and drill the holes through. Put the boards back into place, insert the two elevator bolts through the holes (or carriage bolts if you can’t find elevator bolts), put your temporary weight back on the board, and go back under the car to finish by bolting the retention strap into place using washers and lock nuts.

The next step is to take a big hammer and bash the angular battery tray straps that extend from the frame tube down to the battery box frame in a slightly outward direction to allow the container to drop in. A couple good whacks is all it takes.

Find the middle of the nylon strap and screw it into the block after putting the snap ends on. Put you your container in, snap the snaps, and voila! you have just gained the space that you need to put those miscellaneous repair pieces so that your navigator can take that extra bag!

Colyn Firth in South Yorkshire, UK, wrote:
"I came up with a similar idea for storing essential spares a couple of years ago. It has proved very useful and has made my MGA experience a much more mellow one! Also I have found that for some reason my car generally seems to attract many more people to it than other MGAs seem to, especially after I have removed the battery cover. I call it my essential breakdown kit"! -- Colyn

Here's another one from Gary Edwards in Kernersville, N.C. USA.
"I put a standard plastic box in my extra battery hole".