So I have managed to find a way to make this somewhat less labour intrusions using a python script hosted at the following Github location:
https://github.com/tvheadend/tvheadend/blob/master/lib/api/python/tvh-json.py
Initially the script would throw an error but I was able to modify line 155 from:
jdata = json.loads(jdata.decode('utf-8'))
to
jdata = json.loads(jdata)
to export the muxes from TVheadend use the following command:
TVH_USER=<replace with TVheadend username> TVH_PASS=<replace with password> python3 tvh-json.py exportcls iptv_mux> outputfile
E.G TVH_USER=me TVH_PASS=mypassword python3 tvh-json.py exportcls iptv_mux> output.json
I then did a simple copy and replace and then imported back into tvheadend using the following command
TVH_USER=<replace with TVheadend username> TVH_PASS=<replace with password> python3 test.py import < outputfile
TVH_USER=me TVH_PASS=mypassword python3 tvh-json.py import <output.son
Obviously this requires that Python3 be installed. Thanks to perexg for providing the script