Hi everyone,
Thank you all for your input
I am really sorry I haven't replied for such a long time, I was unwell last week but before that (since my cycle had stalled) I decided to strip down the tank (14th November) and redo everything the way I originally wanted to (before the LFS put me off). I put in planting substrate under my gravel and fully planted the tank on 17th November. I also upgraded my LED to a fluval plant 3.0 59W (which I think is not enough for the plants I have got now

) and I am injecting CO2 and using a solenoid valve plugged into a timer so it goes off overnight. My pH has stayed at a relatively stable 6.6 - 6.8 every day. I was worried about it crashing but since starting up the CO2 on 17th November, its stayed the same thankfully.
For reference, I have about 50 plants in there since I ordered a lovely mixed box from Aquaessentials that said it was for 200L but quite a lot turned up so it's pretty full

.
So at the minute I am re-doing my cycle and have had better luck this time I think, but I am still getting some odd readings. My ammonia finally drops and stays at 0 within 24H, but strangely I have not seen any nitrite or an increase in nitrate, despite testing every day (twice a day in the first week of set up). I am also doing weekly water changes. I am quite confused with these results and I am unsure how to progress from here.
In reply to the other posts:
Jaypeecee:
Thank you for your reply

1. My pH was maintaining at 6.8 - 7.0, but has dropped slightly since I started injecting CO2 (as I stated it is now 6.6 - 6.8 ).
2. Ah, unfortunately I don't have the bottle anymore, but I remember it was at least the beginning of 2019, but I can't remember the exact date. I did check before I added it and wouldn't have done so if it was borderline/out of date. Even the new batch I put in when I restarted was in date. Yes, I did shake it well.
3. I bought a phosphate test and I am adding it as part of my fertiliser regime. I got 5ppm last week, which seemed too high.
4. I had an airstone running 24/7 and I have a reasonable amount of surface agitation from the filter. Unfortunately I have to switch the airstone off whilst the CO2 is running but that wasn't an issue for my original cycle as I just had the airstone.
Matt:
Thank you for the link

I will check it out. Since I planted it, I will probably start another thread, as there would be quite a lot to cover

Hampalong:
Unfortunately, I made things complicated by re-doing my tank from scratch, I did start a new cycle with new bacteria and added more biomedia to the existing stuff in the filter.
It seemed to kick start the cycle enough that the ammonia will now completely disappear over a 24hr period and I am doing weekly water changes as I said above, but again, it seems to be stuck not showing nitrite or nitrate and the last 2 water changes haven't made a difference just yet, should I do a larger water change every week instead of the standard 25%?
Again, thank you all for your time and I apologise for writing back so late and complicating everything.
Kind Regards,
Jade