Welcome to the forum
The ticket is here:
http://www.brfares.com/#faredetail?orig=EXD&dest=BTN&rte=828&tkt=SVR
OUTWARD TRAVEL
Not valid on trains timed to
depart after 04:29 and before
09:00 except as listed below:
06:55 (and all later services)
Weymouth - London Waterloo:
boarding at stations Weymouth
- Bournemouth inclusive.
06:41 (and all later services)
Exeter St Davids - Waterloo:
boarding at stations Exeter St
Davids - Tisbury inclusive.
But what itinerary do you have in mind?
You may want to have a play with
www.fastjp.com (times only; no fares) which is very flexible in terms of via/avoid stations.
If you can get it to generate an itinerary to your liking, you can then check the fares using
www.trainsplit.com (a fee will be charged only if a cheaper "split" fare is found; if the through fare is cheapest there will be no fee) or using
www.trainscanbecheaper.info (no splits & no fees).
I see that if you depart 0641, you arrive into Southampton at 0928. In practice, you might make the 0932 but this is not an official connection. The next official connection would be the 1032. But you don't need to leave Exeter at 0641 to make that! The 0725 will suffice.
So journey planners will not -
unless you specify additional interchange time at Southampton - give you an itinerary departing 0641 onto the 1032. You can specify this additional interchange time using trainsplit.com or trainscanbecheaper.info, and then get the earlier train if you are able to.
(I think you'd be best alighting from the
very front of the train at
Southampton; your trains are booked to arrive platform 2B and depart platform 2A.)