Is there any slight give in the newel?
Only way I can see is by cutting a channel in the newel and filling afterwards. Wouldn't be pretty though. Very odd design really.
Other option is remove the screw and fix externally from the underside. Not sure it'd be robust though.
That is weird as there is no water at that fitting. My guess would be that water is getting into the recess when you shower and then making it's way out afterwards.
If you look at the fitting it appears slightly misaligned with a gap at the top which would allow water to get in.
You can get shorter pan connectors. Look on Screwfix, there's a wide range available.
Concealed cisterns are a pita to work on. Yours looks tricky as the flush pipe (smaller one above soil connector) needs to be cut to allow the pan to go further back once new pan connector is fitted.
Is...
If it's the toilet Flexi that's leaking you'll need to shut off water, flush cistern so it's as empty as can be and then pull the toilet pan forward to access the waste pipe.
The toilet looks to be siliconed across the top and maybe around the bottom. It should also be fastened to floor with...
They are easy to fit, good adhesive like no more nails will fix.
Depends on finish you want whether you remove coving and skirting. If the panels are quite deep they'll sit proud of the coving and skirting. You have to choose if you can live with that. If you fit them over the top they'll...
i've always used this one. Customer service is good if you need it and they just send you an invoice prior to direct debit. I've used that all over france.
https://www.atmb.com/