Patio makeover- the hardware bit.. (long and not very interesting alert)

[erebus]

I am not expecting any replies, tbh, but here goes:

I have a concrete area, 2.4 x 3.2 m in a corner of my garden (old Wendy house base, I think). It's intact but not very smooth, and not at all attractive. A path leads to it from the conservatory, it's just a line of buff coloured 'municipal' pavers, 60cm squared. It's in good condition, BUT, oddly, it's been raised up a bit (3"?) AND it juts into, or rather over the concrete. You step down the 3" onto the concrete. Guess they didn't want to cut a paver in half! But this means that I have to build up the concrete to get the new top level with the existing paver path.

Currently I have a grand display of hostas in pots and my potted herbs standing on the concrete. I don't anticipate putting a table and chairs on it but I need to make it nicer.

Now, as luck would have it, I have 10 setts of these!, salvaged from a skip which I want to use. My plan is to buy 9 more buff pavers (45 cm square) and form an L shape in a corner to stand the hostas on, and to fill the rest with these setts.

How to DO this?

My thoughts are to lay a border of the sett cobbles (they're on strips of plastic so you can cut to any shape) and cement these in place onto the concrete, raised up enough so their tops are level with the path paving.

I will then do the same with the new 45cm pavers, placing a daub of cement, putting the paver down (so they, too are level with the path).

Then I will fill the middle with hard core (fine stuff) straight onto the existing concrete slab, including putting some under the pavers as far as I can and then lay the setts onto beds of sand on this. They won't be able to slide sideways because they will be bounded by cemented-in cobbles.

I will then mortar/grout the lot.

I won't put decorative gravel in between the gaps as the area gets a bit messy with tree-drop and you can't sweep gravel!

The thing is- will this work? Is cementing pavers onto existing concrete going to work? Will the hardcore base underneath the cobble setts subside badly?

I would post on DIY-Not but you get boufhead blokes patronising you on there or demanding that you have to get a professional in as you evidently don't know what you're doing otherwise you wouldn't be asking...

Things that spring to mind:

a) put planks of wood round it to keep it all 'on top; until it drys
b) you will need to grout the setts - I think a dry cement mix brushed in then watered lightly is a good way to go
c) will the cobbles/setts be the same height as the pavers
d) is the only reason not to cement the setts to save time/money.....I'm not too sure about that but I don't know why

ps I am not an expert

I asked DH (he does this type of thing) and he said to make sure that the concrete is clean. If you have a pressure washer give it a good wash over to make sure it is clean. DH said use a cement/sharp sand screed. Make sure the mix isnt too dry and put the slabs/stones down while the mix is still wet. Grout use a dry mix as a wet mix will get all over the slabs (brush dry mix in).

Thanks very much for your useful replies!