The SRA, last Spring, asked for a service as follows:

Swindon to Southampton through services are discontinued;

One Swindon peak service operates in each direction between Westbury and Swindon calling at Trowbridge, Melksham and Chippenham. One additional evening round trip also operates between Westbury and Swindon. This represents a reduction, from five round trips a day to two round trips a day, via Melksham

What is proposed does NOT meet this specification.

1. There are NO peak services.  First are proposing a service to Swindon in the morning BEFORE the peak, and returning in the evening AFTER the peak.  They are using a train that spends its peak time on the Cheltenham to Swindon line, and they're "stealing" it from that line for a couple of Melksham runs off-peak.

2. The ADDITIONAL trip is not in the evening in the Swindon to Westbury direction - it leaves Swindon at about twenty past six in the morning.

Maybe, but I find it hard even under the loosest of specs to think of 06:20 as "evening" 

This needs to be brought to the attention of DfT Rail - suggest you contact Peter West the Franchise Manager.  You need to be quick though as the timetable is currently with Network Rail for validation and once this is complete in July it will be set in stone.