TOPIC:

You are correct in that the small screws are the only thing holding in the choke plate.  Also note the dimples on the plate, forcing it to be installed/removed from one side only.  If the plate doesn't come out easily, it's because it's bent, and you may need to use force.  When you replace the screws, be sure to use RED loctite, the permanent type.  Loosely install the plate/screws, actuate the choke to make sure it moves smoothly, then tighten the screws evenly, and double check the plate/shaft movement.

As its the bottom half that's bent it doesn't look too hard a job to straighten it in situ. It's only thin sheet which parallel jaw pliers would sort. 

I’ve put the carbs back on my bike and it starts, runs, and idles ok. 

Thank you EVERYBODY here who helped me. I’ve learned a huge amount and resolved the original problem, to replace the perished intake boots. New problems along the way, also fixed. 

I didn’t do a full strip down, but I will. I needed to reinstall it in my bike, just to give me the confidence that after the changes and tests I’d done, all worked ok. I can tell it’s not running perfectly yet: the occasional pop from the exhaust and the idle fluctuates between 900 and 1300. When I did a wet test, the RHS carb looked good, the LHS one was odd and seemed to defy logic: the petrol didn’t sit level on each side of the bend. It was a bit higher on the end AWAY from the overflow outlet, and neither side was close to where the bowl meets the main body of the carb. Yet the bowl was filled with petrol and when drained seemed to contain a similar volume to the RHS bowl. 

Next time, when I’ve got more free time, I’ll follow the common sense advice from many of you, and fully strip it, clean it, straighten the choke plate, investigate the wet test observation, and remove, clean, and replace the petcock filter. For that, I’ll start a new forum topic. 

Meantime, I’ll order replacement o rings for the rebuild, buy a compressed air can, read relevant forums here, and be much better prepped. 

Thanks again all. My baby is back on the road