Ive managed to crack it with the following batch file:

@echo off

set hour=%time:~0,2%
set minutes=%time:~3,2%
set seconds=%time:~6,2%

set year=%date:~-4%
set month=%date:~-7,2%
set day=%date:~-10,2%

ffmpeg -i "http://a.files.bbci.co.uk/media/live/manifesto/audio/simulcast/hls/uk/sbr_high/ak/bbc_radio_scotland_fm.m3u8" -c copy -t 00:00:20 "Jazz Now %year%-%month%-%day% %hour%.%minutes%".ts

I set this up in Task Scheduler to run every 5 minutes which generated the following file names:
Jazz Now 2018-05-08 21.41.ts
Jazz Now 2018-05-08 21.46.ts
Jazz Now 2018-05-08 21.51.ts