Thanks for the help man, it's much appreciated!
I have just one last question, so, how do you get back to stock when you want, to be exact how do you flash a stock firmware back?
I had a Sony device before this so I had to just download a firmware file and flash it with the Xperia Flashtool. Is it much different for Huawei devices?
Ask on the corresponding forums/threads for stock recovery img - you can flash it back the same way as you will flash TWRP. There is also an ADB command to make your own reovery image (?).
Once you flash TWRP, make a complete backup of all partitions, particularly the (non-rooted) boot partition.
Hence you can always restore stock partitions from TWRP and then the stock recovery. You will probably need that for futurebOTA upgrade.
Few more hints:
-Bootloader unlocking code is free, you don't need special programs and credits (10 bucks) to obtain the code and unlock (do it yourself via adb/fastboot). You probably need to open Huawei page from PC, there are no EU states to choose, claim Hong Kong with Eglish, fill SN, IMEI (first IMEI if dualSIM) as asked, it will give you the code immediately (I did 5 months ago,np).
-First install Huawei HiSuite to PC (and Huawei) and make backup of everything (contacts, call log, all apps...). Unlocking bootloader forces hard-reset, you will need to restore your things via HiSuite upon the hard-reset. Ome things also restore via Google account.
-Once you flash TWRP you must first/immediately boot to TWRP, otherwise stock recovery will overwrite. ADB/fastboot instructions are elswhere (and in the OP of the XDA rooting thread you cited yourself). Before the final Enter, press and keep pressing Vol+ and Pow simultaneously. Enter, then immediately unplug USB. Release Pow only when Huawei displays Booting. If you don't follow exactly and timely, you must flash TWRP all over again. From TWRP boot to System, later you can boot to TWRP as usual with Vol+ and Pow, or (upon rooting), install Reboot app to boot to TWRP programatically.
PS:
-You can also hard reset to the (last installed) stock firmware (by restoring the stock recovery, too) by 'dialing *#*#2846579#*#*, it gives you a menu with options.
-Or (very usefull), install FirmwareFinder (GooglePlay, XDA), download FullOTA-MF-PV firmware for your model, extract update.app from the ZIP and put to DLOAD folder on SD card (root path). Boot by simoultaneosly pressing Vol+, Vol- and Pow, it will flash the given firmware.
-Relocking bootloader also hard resets to stock fiirmware and recovery. Ie, with the unlocked bootloader phone claims that it is unsecure on each booting, but if you relock bootloader you loose TWRP and root.
In some cases hard reset or DLOD may fail (may even brick the phone), it is better to first restore stock partitions in TWRP (I also flash then stock recovery), before hard resetting or DLOAD upgrading.