Link 0, Grade 9, was created by adding workstations to Link 1 and splitting the link (to try and reduce a bit of the workload) Link 0 currently do Paddington and Acton. There will be a new workstation between the two called OOC at some point.
Link 1, Grade 9, is Hayes, Heathrow and Slough. Both these Links work 12hrs 07:00/19:00
Link 2, Grade 9, is Twyford, Reading, West Junction and B&H. 12hrs 06:00/18:00
Link 3, Grade 7, is Didcot, Oxford and Swindon. 12hrs 07:00/19:00
Link 4, Grade 8, Bath, Bristol TM and Stoke Gifford. 12hrs 07:00/19:00
A Crossing desk, Grade 2, with Appleford, Stocks Lane, Causeway and Minety Crossings on it. 12hrs 06:00/18:00
I worked Link 1 in its original 4 workstation form but I don't know the exact current shift patterns are, I left there about 20 months ago.
Hope this helps.