I keep staring at the pics, Jo, but I can't see that anything is the wrong way around.
By all means try what Etch suggests.
However............... in my experience, the joints usually require undoing and re-connecting using ptfe tape.
https://www.screwfix.com/p/ptfe-tape-for-water-12m-x-12mm-10-pack/63859
It's not a particularly difficult job, but I honestly wouldn't suggest you try it yourself.
You'd need to drain the system... then re-fill... then watch it dribble again if the joints aren't made properly.......... and so on.
Best left to a plumber. They know all the things that can go wrong.