Handyman dispute - how best to deal with this

I instructed a local company (one-man band) to do some work in my rental property. The full list of work was as follows;

Plaster front room.
Make good and plaster small area in bedroom around new Windows
Repair small section of external render.
Fix leaking gutter.
Repair cupboard door
Box in gas pipe in conjunction with front room plaster
Fit skirting in front room
Repair coving in bedroom.

For information, he subcontracted the plastering out, with my knowledge of him doing so.

All in the final invoice total is £1150.

All the work is now complete, however during the work the following happened;

Plasterer put no protection on floor in front room while plastering. Multiple attempts by both parties to fully remove have failed as there are a lot of small holes and marks that now have ingrained plaster in them. White marks over a lot of the floor do not really look good.

Plasterer decided not to bother with either asking me to, or doing it himself, take the radiators off the wall while making good the bedroom. As he was unable to get his tools into the small gap between the window cill and the radiator, there were a number of large holes left. Along with this, the blending in where possible was not great. Basically, I had to do a lot of sanding and filling to get this looking presentable.

Framework around window was not straight, there was a 3cm difference between recess at top and bottom of windows. The framework also did not fully cover the edges of the window frame, so there were gaps visible. While the windows themselves were possible not straight, I would have expected the framework to match and be the same size all round. I would add that the front of the recess and back of the recess were different measurements again.

No protection given to multiple sockets which were hanging out of the walls for plastering meaning they ended up with masses of plaster all over the wires. I was forced to replace one of the sockets and did the rest to match (please note this is at my expense).

Plaster all over radiators in bedroom and large lumps of it between the fans.

Plaster/render splashes over the decking in the garden. Although this has mostly been cleaned up, they are still partially visible.

Plaster/render splashes outside front of house. Again, mostly cleaned up now, but still visible to some degree.

Guttering quite possible still leaking after 2nd attempt to fix. Not been there will raining to confirm.

What I have had to do since he told me he had finished;

Revarnish the floor in a darker shade to hide the white marks. 2 hours for prep, 2 hours to paint + £50 for varnish

Repaint fireplace walls to cover plaster marks - Had paint, so just my time - 1 hour

Replace sockets - no cost element here, just time - 1 hour

Replace radiators (although I was toying with the idea anyway, he forced my hand) - no cost element attributed to him here, just time. - 2 hours

Fill holes in wall - 2 hours +

Add UPVC trim around windows to hide differences in framework and windows - 2 hours time.

So basically, I do not feel I should be paying the full amount. I have already paid him £740, that was £240 for materials and £500 once the plastering was complete (my gesture, he did not ask, although I am regretting this now)

So, I owe him £419.

I intend to suggest (tell him) a reduction of £150 based on the following;

£50 for varnish
£100 day rate (very cheap, try getting someone at this price) for my time to fix issues that he tried to, but didn't or those I had already fixed. I gave him multiple chances to resolve the floor and on the last occasion told him to put key through door once complete, which he has done.

Does that sound fair, and reasonable? If not, why not? If so, how to approach as he sent invoice Saturday and will want paying fairly soon.

Thanks