Timing my ruby

[Pearls not a Singer]

2 things may help

Is the engine correct for the car? i.e. is the engine number a little in excess of the chassis number. If this correct then the fly wheel covering should be removable with a little
fiddling

If you can see the flywheel marks, the timing is best set with a timing light at max (3000) revs - start with 26 degrees at the flywheel then road test. A litttle more advance may be beneficial for max power but no more than 29 degrees if you want to be sure of not damaging the engine.

You can check the  reading for a series of revs to check that the distributor is advancing from idle to max revs

[dickie65]

I have never used a timing light on a Austin Seven in over thirty years of ownership.
I just set front cylinder to TDC on compression and turn the dizzy till the points just open.
This should be good enough to get the engine running then adjust the timing for best tickover speed.
Then do some road testing to fine tune further.