Wales & West started operating the franchise in October 1996. This was mid-timetable, so I'm assuming that they merely continued with the timetable they inherited from Regional Railways. The September 1996 to May 1997 timetable shows a (more-or-less) hourly clockface service between Manchester Piccadilly and Cardiff Central between roughly 7.30am and 7.30pm, with the last train as far as Shrewsbury a couple of hours later. A handful of these hourly trains were extended further south/west:
1233 SuX Manchester Piccadilly to Milford Haven, arr 1850
1933 SX Piccadilly to Bridgend, arr 2322
0645 SX Carmarthern to Piccadilly, arr 1202
0650 SO Bridgend to Piccadilly, arr 1038
0900 SO Carmarthern to Piccadilly, arr 1402
1225 SuO Carmarthen to Piccadilly, arr 1915
1530 SuO Milford Haven to Piccadilly, arr 2151
I'm assuming that W&W had rather more input into the next timetable, from 1st June 1997 to 27th September 1997. The basic hourly frequency between Manchester Piccadilly and Cardiff Central remained, but the number of 'exotic' through-trains suddenly burgeoned, and were mostly extras rather than extensions:
0712 SX Maesteg to Piccadilly, arr 1112
0645 SX Carmarthen to Piccadilly, arr 1202
0600 SX Portsmouth Harbour to Cardiff Central/Liverpool Lime Street
0641 SX Penzance to Piccadilly, arr 1436
0840 SX Milford Haven to Piccadilly, arr 1502
0650 SO Bridgend to Piccadilly, arr 1038
0745 SO Pembroke Dock to Piccadilly, arr 1402
0620 SO Penzance to Piccadilly, arr 1436
1110 SuO Pembroke Dock to Piccadilly, arr 1848
1333 SuO Penzance to Piccadilly, arr 2110
1525 SuO Milford Haven to Piccadilly, arr 2208
1059 SX Piccadilly to Penzance, arr 1906
1233 SuX Piccadilly to Milford Haven, arr 1850
1300 SX Liverpool Lime Street (& Cardiff Ctl) to Portsmouth Harbour
1933 SX Piccadilly to Bridgend, arr 2332
0933 SuO Piccadilly to Penzance, arr 1721
1354 SuO Piccadilly to Paignton, arr 2028
The Winter timetable, from September 1997 to May 1998, was different again, with the following exotic extras to entice the brave and/or foolhardy:
0712 SX Maesteg to Piccadilly, arr 1112
0645 SX Carmarthen to Piccadilly, arr 1202
0600 SX Portsmouth Harbour to Cardiff Central/Liverpool Lime Street
0615 SO Penzance to Piccadilly, arr 1438
0641 SX Penzance to Piccadilly, arr 1438
0840 SX Milford Haven to Piccadilly, arr 1502
1517 SX London Waterloo to Piccadilly, arr 2140
0650 SO Bridgend to Piccadilly, arr 1038
0900 SO Carmarthen to Piccadilly, arr 1402
1418 SO London Waterloo to Piccadilly, arr 2039
1225 SuO Carmarthen to Holyhead/Piccadilly, arr 1845
1325 SuO Penzance to Piccadilly, arr 2110
1530 SuO Milford Haven to Piccadilly, arr 2150
0759 SX Piccadilly to London Waterloo, arr 1413
1059 SX Piccadilly to Penzance, arr 1906
1233 SuX Piccadilly to Milford Haven, arr 1850
1300 SX Liverpool Lime Street to Portsmouth Harbour, arr 1949
1933 SX Piccadilly to Bridgend, arr 2332
0659 SO Piccadilly to London Waterloo, arr 1312
0933 SO Piccadilly to Penzance, arr 1722
1354 SuO Piccadilly to Paignton, arr 2011
The timetable remained largely the same, with a few minor re-timings, until the start of the Summer 1999 timetable - which is where a gap in my archive starts!
I am assuming that W&W must have offered cheap tickets and had plenty of special offers in order to persuade people to spend up to eight and a half hours on a Class 158! (I didn't actually look to see how long the Piccadilly to Penzance Virgin Cross Country services took - maybe tomorrow!)
Wales & West seemed to have a penchant for running exotic services; a glance at Table 56 in the Summer 1998 timetable shows the odd through train between Birmingham New Street and Fishguard Harbour, a Birmingham New Street to Barry Island (and return service to Birmingham International), and a Birmingham New Street to Swindon via Gloucester, among others.
Phew!