I removed the new TPS, compared it to the old one including the angle of the inside bit.
I've re-installed the new TPS. . . checked a few You-Tube videos to see if I've missed anything. . . all looking good.
Did 2 x test drives, 1 from cold and 1 hot.
Both times it starts, holds 1800-2000rpm then slowly drops to around 1200rpm.
Take it for a drive and it's stuck in first gear until 3000rpm on a mild throttle and up to 4000rpm if I go even softer on the throttle.
As soon as I sink the boot into the throttle it changes up to top gear.
Kinda like it's doing the opposite of what it's supposed to be doing, holding the gear under low throttle and changing up when it should be changing down.
I re-did the Throttle body cable adjustment as suggested by ApacheResistance below to see if that made any difference and took it for a third test drive and it made no difference.
The TPS oly appears to fit 1 way and the inside part only turns 1 way so I can't see how I could have incorrectly fitted it, but open to suggestions.
I'm thinking the TPS may be faulty and sending reversed outputs to the ECU.
At least the misfire and shudder seem to have gone (although the shudder was only occasional) so it looks like that was likely to have been caused by the TPS.
I'll see if I can get ahold of a genuine Jeep TPS and if that solves the latest problem.