Swipe is not /data wipe. Yes you have to do a full wipe a.k.a factory reset, this rom might have a different partition layout, not sure though.
Yes it will erase everything on the device and that's the point then put back the rom and your gapps, flash them and you are good to go.
Sorry I'm still confused. You said I "have to do a full wipe aka. factory reset", but this is what I've already done, and what I meant when I said I've tried doing the standard wipe.
Ergo,
a factory reset is what I've already tried doing (which wipes Data, Cache, and Dalvic). Even after doing this the installation of Lineage throws Error 7.
There are two other wipe options to choose other than the standard factory reset:
(01) Format Data - which sounds a bit drastic, and wouldn't this wipe literally everything, including my internal storage which contains the rom I'm trying to install?
For the record it states this:
"Format Data will wipe all of your apps, backups, pictures, media, and removes encryption on internal storage. This cannot be undone. Type yes to continue. Press back to cancel."
(02) Advanced Wipe - Which is basically showing a series of sections for me to choose which parts get wiped. Presumably if I tick all of them that would result in the same as option (01) above, 'Format Data'.
The options to select to wipe here are:
[ ] Dalvic / ART Cache
[ ] System
[ ] Data
[ ] Internal Storage
[ ] Cache
[ ] Micro SD Card
[ ] USB OTG
Cheers.
EDIT:
Sorted it. It did require the format, and it did erase everything in the internal storage except for couple of folders (forget which ones) but it doesn't erase anything from the SD card, where I installed Lineage and Magisk from. Before flashing the rom and Magisk I also used the 'advanced wipe' section and wiped the dalvic, system, and cache. Then rebooted back into recovery (TWRP) before performing the flash.
There is a great guide on these processes here:
https://andi34.github.io/faq/faq_twrp.html
Thanks again for your help, and also to the Lineage dev for producing what appears to be a great custom rom
