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It's the only candidate listed in 1963, but with the number of listings counted on your fingers and in one month only, I would find it hard to believe that they had no more Ed.1 pennies for a whole year. Also, the IIIe was listed at 15/-, so either it didn't sell and was repriced at a later date, or it's a different coin. But it wasn't in the April 64 list which was quite extensive, and the other thing not in its favour is that a purchase date in 1963 doesn't leave much time to include it in the January list prior to printing.

Anything on the other side of the Seaby ticket? No IIIds of Newcastle in either 63 or 64. One IIIe in January 1963 and a whole raft of Edward pennies in April 64, but not one was a Newcastle. There were only a handful of Ed.1 pennies listed in the whole of 1963, so suspect these were too common a type to bother with. They made a good profit on it.

This of course makes it one of the very few coins with two different dates on it 1848 and 1849

None!

Wishful thinking, I'm afraid. The 8 over 6 type is very clear as can be seen below (courtesy of Richard's penny website). Having said that, yours has signs of doubled entry/strengthening on the 1 and the 6 of the date, so the 8 too might have had work done...

I haven't bought much lately but I did get this from the Sovereign Rarities auction - unusual wide date.