I haven't demoed either of the amps you mention but did demo various Denon amps of a similar era, from memory the AVC-A1SE vs AVR-3801.
The A1SE was noticeably better but I ended up with the 3801 due to cost and priorities (music - dedicated stereo system).
I think the AVC-11SR was the next one down from the A1SR (A1SE replacement) so should be amazing.
Saying that though, the AVC-A10SE that you have probably won't be far behind as I presume its the previous model or 3 from the A11SR? It might only be a slight improvement, a bit like me going from a 3801 to a 3803.
Not sure what I would do but unless the AVC-A11SR has features you want that the AVC-A10SE lacks than you might as well put the money towards something else or save it in case the amps ever need servicing.
Thanks for your comment. Yea the Sr was the replacement for my se It has the 7 channels whereas mine has the 5 but I use the poa to make up the other 2. I would love the a1 but even now I cudnt afford My a10 is suffering from dry solder joints at the min but Whos to say the 11sr will not be the same?? Seller says any test welcome but I'm still undecided tbh....