I've been playing around and managed to get comskip to work with my AMLogic S912 box.
I'm not sure whether all of the following steps that I used are necessary as is was a case of try this and that until it worked but this is how I achieved it.
1. SSH into the box and create the directory /storage/.kodi/userdata/addon_data/tools.comskip
2. Install the Comskip addon tools.comskip-8.2.90.zip from post #22 for RPi2/arm courtesy of shanemeagher.
3. Fire up TVHeadend on your browser and navigate to Configuration, Recording.
Choose your profile name of choice from the left hand window pane (probably Default profile unless you have created one for specific needs).
Scroll down the options in the right hand pane until you get to Filename Options and check the boxes for Replace whitespace in title with '-': and Remove all unsafe characters from filename:. Also make sure that your chosen profile is Enabled.
Scroll back up a little until you see the option Post-processor command:. In this field enter the text /storage/.kodi/addons/tools.comskip/bin/comskip.bin --ini=/storage/.kodi/userdata/addon_data/tools.comskip/ini/comskip.ini %f
In the left hand pane, click the Save button.
4. Reboot your box,
5. Set-up a timer recording for a programme that will have adverts (note that if you ever stop a recording part way through then post processing will still be carried out).
6. Wait for the recording to finish and then SSH into your box and navigate to your recordings folder. In my case it was /storage/recordings
Navigate your way into the folder containing the recording, named after the show you just recorded.
You will initially see 4 files but don't do anything until post processing is complete and you see the 5th, which is the .edl file.
7. Open the video in Kodi and when the ads begin, the video will skip the ads and you may even see a small pop-up in the bottom right hand side of the Kodi screen with the word Commercial, to indicate that it has reached a point and is skipping it.
Ensure that the .edl file always remains with the video file if you copy it elsewhere.
The other .log and .txt files can be deleted unless you want them for further diagnosis.
A big shout out to all that have contributed and given the answers by their own sheer efforts of trial and error.
I'm using Build: 4.2.5 ~ LibreELEC Tvh-addon v8.2.113 (2017-12-21T20:30:12+0100) of TvHeadend.
Update: I noticed when using this with a current X86/64 build based on Kodi 18 and although the addon would install and there were no errors, there was no post processing.
I then tried an 18 based distro for S912 and it didn't work either, so for now it will only work on Krypton 17.6 builds for AMlogic/Intel.