My USB OTG cable arrived and I found TWRP can access a USB drive, after performing a backup I have installed Cloudy. This has solved my lack of sound when typing, came with the option to use LTE 4G and the GPS seems OK but I will know more when I go home.
While I was fiddling I also tried to change my bootanimation.zip, I accessed system/media and changed the file but the animation stayed the same. Eventually I found a folder called 'cust' and in there were folder startup and shutdown in which were the animations. This may be just down the SFR TOT ROM I was using.
Things I would do different, and I am not a novice at this:
1. Check the exact D802 version, in Australia it's D802T and when I installed TWRP for the International D802 I was no longer able to boot into Android and use my phone - bu**er!
2. With TWRP working back the ROM onto a USB stick, just in case you choose to wipe the whole phone while frustrated - yes I did this, again, bu**er! I did find that the USB stick must inserted while the phone is working (booted fully into Android) for its first use. It then happily mounts in TWRP
3. Choose a ROM that is confirmed for your model. I wanted Pardus HD but it just doesn't boot for me with the D802T. Cloudy works nicely though.
4. Enable 4G by choosing mode 'GSM/WCDMA/LTE Auto' by going System settings > Tethering & Networks > Mobile Networks > Network Mode. If the option isn't there Google the fix but I used ES File Explorer (phone rooted & system mounted as RW) to edit the build.prop file in 'Device\System'. Changing '#ro.telephony.default_network=9" to "ro.telephony.default_network=11' I am on Optus and the post I read also offered 13 as an alternative number. Cloudy offered the LTE straght away.
5. If the 'Knock On' is playing up then go into LG Hidden Menu (Google this) and then 'Settings\Update Touch....'
I hope this information may help somebody out and many thanks to XDA and contributors for the information I read that helped me solve my issues.