Leamington Spa ?
Not Preston becausePreston?
Not Preston because
1) Preston has 6 platforms not 4
2) Preston has way more than 3 departure an hour in each direction
3) Preston is served by more than 1 TOC (3 iirc)
4) no trains run fast through Preston
All the trains that stop at this station (3 per hour in each direction, I think) are for the same TOC, but three other TOCs run through non stop at least once an hour. It has 4 platforms.
St Denys.
Served by 1tph WAT–POO, 1tph SAL–ROM and 1tph SOU–PMS, all provided by SWT.
Fast trains are 2tph WAT–WEY (SWT), 1tph CDF–PMH (FGW), 1tph BMH–MAN (XC), 1tp2h SOU–NCL (XC), 1tph SOU–VIC (Southern) and 1tph SOU–BTN (Southern).
Platforms 1 and 2 are to/from Eastleigh, platforms 3 and 4 are to/from Fareham.
Coventry?
Not sure about this, but Cheadle Hulme? (Surely the TOC that runs fast through both would be XC...?)

Not sure about this, but Cheadle Hulme? (Surely the TOC that runs fast through both would be XC...?)
Yes. Served by Northern (Manchester - Stoke stoppers 1tph, Mancheser - Wilmslow / Crewe 2tph)
Passed through by ATW (Manchester - Cardiff), Virgin (Manchester - London), XC (Manchester - Birmingham - wherever)
One of the ManchesterCrewe is via Styal, though.
OK guys, have fun with this. I rpomise that the answer is not "South Woodham Ferrers", or anywhere else in Essex for that matter.
This time last year, every passenger service (except a few on diversion) called at this station, which also has a limited freight service running through, but as of May this is no longer true. For a station of its size, it has a very low number of platforms, at only two, and probably has the record for the highest suggested connecting time based on minutes suggested divided by number of platforms (not including those with only one). This station has a regular through service to London, as well as several other notable cities, including one member of the Core Cities Group.
Alderley Edge1tph through Cheadle Hulme only runs as far as Wilmslow (or is it Alderley Edge ?)
Bath Spa ?