It's a Ruland Maksutov-Cassegrain (hence 'R-Mak') rather than a more usual Gregory Maksutov-Cassegrain.
A Gregory Mak-Cass does indeed have a 'spot' secondary on the corrector, whereas the R-Mak has the corrector
in front of the secondary - a sub-aperture corrector. This SkyWatcher design also another corrector in the baffle tube, apparently. The R-Mak is an open-tubed design unlike the Gregory Mak-Cass.
There are other variations on the Mak-Cass, such as the Rutten Maksutov (Rumak) with the secondary separate from the corrector.
There's a Cloudy Nights article on the SkyWatcher R-Mak here:
https://www.cloudynights.com/topic/5...aksutov-300mm/
And, of course, wikipedia:
https://en.wikipedia.org/wiki/Maksutov_telescope
A long time ago, I owned a humble Gregory Mak-Cass. At f/15, it was a surprisingly good scope for casual viewing - very forgiving of eyepiece under-performance.