I finally got some wire in the air. Well, not very much and not very high, but at least it is outside. One end is attached to an eye bolt outside the shack window positioned so I can reach it with the window open wide. From there the wire runs down to the workshop. I am not exactly sure of the length, Google Maps suggests just short of 30 feet. So pretty short! But it works, and the FT450D internal tuner can cope with it from 30m to 6m, except for 12m. Anything lower than 30m has SWR approaching 3 but otherwise it seems to be ok. Pity the sun is being naughty right now but it gets a good spread across much of Europe on 20m.
The wire feeds a 9:1 (I think!) unun and a 1:1 choke, then RG58 (*) to the patch panel. The cable needs to be routed yet as it is currently just running through the open window.
Signals received are definitely stronger than with the loft wire and Z11 tuner but it is hard to say exactly how much because of the time taken to swap leads, disable or enable the internal tuner, and tune the wire during which time the watched FT8 QSOs have ended and moved etc. However, with the TS2000X on and connected to the loft wire a random Italian FT8 signal was -17 on the TS2000X + loft wire and -9 on the FT450D + new external wire. Plus the waterfall on the two rigs definitely shows the advantage of the external wire. In fact, the wire length is probably similar to the existing loft wire.
So now I really must get round to running a wire up the garden which will be a lot longer.
(* Typical. I put RB58 instead of RG58, didn’t proof read, turned everything off for work and just got back to edit it now!)