On 7/7/2021, Dean Tedesco in Australia wrote::
"I'd got a couple of 6V batteries last week and decided to install them, but when I went to pull the old ones out the spare wheel was in the way so I pulled the boot lever to open the boot and to my surprise it came out about 12 inches past where it should have and the boot stayed shut. After about 5 minutes of expletives I jumped on the internet to see if anyone had any tricks to get into an MGA boot without the pull rod still attached. The consensus seemed to be to drill a hole in the bottom of the boot to get to the boot release mechanism. I was feeling a bit bummed as I wasn't keen on destroying my boot or pulling half the car apart for the sake of a 2 cent split pin. I also was afraid I'd drill in the wrong spot and be left with a sieve for a boot.

Then the solution came to me. .There is a small hole behind the seats about a centimeter in diameter that you can access the boot from. This hole is big enough for an endoscope camera, which I just happened to have one in my toolbox from a previous issue with some pipes I needed to inspect. So I attached a metal coat hanger to it to stiffen it up and this gave me the ability to pass the camera through the boot all the way to the back to get a visual on the boot release mechanism. Once I located it I was able to easily relocate the rod in the release arm and pull to open the boot. This was a really straight forward and painless operation and saved me defacing my car. Woohoo!. Anyway boot was open so I could replace the split pin and install the batteries which meant I could go for a drive.

View from behind the seats. -------- The camera next to the pull rod.

The camera is relatively cheap, I think from memory I paid about $50 from Amazon a couple of years ago. It's come in very handy many times so far.

P.S. Here's a link to a newer version of my endoscope on Amazon as an example".
https://www.amazon.com.au/dp/B07GVC2886/ref=cm_sw_r_cp_awdb_imm_GNDYZMK59Q2ZT9DD4HNH

If that spare hole is not there in the rear bulkhead of your car, you may be able to insert the endoscope camera over the top of the rear bulkhead panel