Spotted this today which could be the perfect solution for me.
Basically an XLR adapter with phantom power that plugs straight into a phone, tablet, laptop etc. So I can record with my phone, which has excellent video quality, but use a good quality mic to pick up the audio. Might be worth a punt at under £40.
https://www.thomann.de/intl/tc_helicon_go_vocal.htm?i11l=en_GB%3ABG.GBP%3AEUR