I think the TAL150K is a kind of maksutov the corector is in front of the secondary instead of behind.
Here is a review on them
https://www.cloudynights.com/article...the-mk-67-r805
I have seen them for less on Gumtree than what is being asked but condition can vary as they have been made in various time frames. For that Price a Skywatcher Maksutov 150 would be far better, there is one in the Classifieds section. If i had the money i would be buying that one to replace my C6.
There is also a 127 there and 180 any of these would be much better than the TAL150 imho. And then there is the EQ mount on that one with RA drive only, Equatorial mounts are not really something I would recommend for beginners. Alt/Az are far easier to deal with.
Here is an older version of the 4SE.
https://www.gumtree.com.au/s-ad/tura...ope/1200172404
Looks like a Star Discovery type with a 5" Mak this is a nice combo and you could likely change the OTA to a 6" but its in SA.
https://www.gumtree.com.au/s-ad/bank...ion/1200613723
Goto 8" dob good price.
https://www.gumtree.com.au/s-ad/well...ian/1200494699