You do not need IRJs (Insulated Rail Joiners) with Hornby points. All their track along with Peco Setrack is self isolating.
In your drawing you only need a track feed in the siding on the inside end of the turnout point near C for the headshunt/spur siding. The other two - one near A and the other on straight that leads into the siding from the main line are not really necessary.
Point 1 allows power to flow towards C when its set towards the siding. Point 2 allows power to flow into the headshunt/spur siding when its set set towards A.
I have shown the two sets of feeds removed,
Fantastic, thank you.
As a general answer to queries throughout my thread, the track is indeed already laid, including 'rusty' track painting and ballast - I'll upload a pic when I get a chance. We also have a tunnel taking up one of the curves so I won't actually be feeding any connections on that part, but take on board your alterations and will let you know how I get on!
Also - my track diagram was from RailModeller Pro software and the track pieces being used are not necessarily the exact parts on that drawing, as much of the parts came from the Bachmann 'Midnight Metropolitan' Train Set that we bought as a starting point for this little journey into the art of model railways that we've embarked upon!
Finally got round to soldering today using this as my reference and it’s worked perfectly. So happy!
Used soldering iron for first time to achieve this. Got rid of the unsightly track connectors that come with train sets. Allows us to finish off ballast in various places. Best of all, can now shunt the engine into the parallel siding. Appreciate that this will get water off a ducks back to many experienced railway modellers but to us this has been a sweet victory. Thanks to everyone for their input, especially flashbang!