Loose olive

[regsmyth]

I'm just replacing the radiator valves, and the old TRV was done up very very tight onto the olive on the pipe coming up out of the floor screed.
I managed to get the old olive off using a technique I think I got from here - adding in a tiny length of pipe and doing up the nut again, gradually lifting the olive up till it comes off.
Anyhow, the pipe has a narrowing where the new olive will go - the olive fits over but is quite loose. Am I being overly optimistic to think that I can get away with it, or is it bound to leak forever and ever?
I could of course cut off the tail and add a new bit, but I'd have to drain more, and probably dig up some screed to hide the new joint.
What would the panel recommend?

 

[Peter1919]

Could you not have just reused the existing olive and so not have to go to the trouble of removing it in the first place?

I would have thought the new fitting would just have to be tightened to the same extent as the old one was to compress the olive enough to make it water tight

 

[regsmyth]

Well the old nut was knackered and I don't think it was compatible with the new fitting.
Anyway, I did the right thing - cut the tail off at ground level and put a new one on, with a slight outward kink as the new fitting is also a bit longer.
All done, give it a wiggle to check - uh oh, somethings loose further down...
dig up more screed, to find a broken joint about 100mm further down where the tail Tees into the 22mm flow.
So, sit back to have a think, knock the breaker in it's box over, onto the blowtorch (now off and cooling), onto the gripper rod.....
hisssssssssss.
This should be in DIY disasters.
Do you reckon it's possible to solder the 15mm tail into the 22-22-15 T without affecting the 22mm joints?
Off to town now for more gas.....