I did it over last summer (12/13) and I guess it isn't so much a typical example, so I'm not sure how much help this'll be tbh
I found out about some STEM placements being organised by a group called
Science Oxford, who were putting people into summer apprenticeship / research-based placements and giving guidance on submitting the report for a CREST Gold award afterwards.
I had a 4-week placement (8h per day, so 160h total) with a web-development company called
White October. Spent the first fortnight learning the basics of what they do and to program in the languages they use, and the second two weeks producing a raspberry-pi-based monitoring system for the services they manage and sites they host.
You'll get a supervisor within the company who should be familiar with placement students or even the whole CREST system.
The report I did based on the placement (I can send it to you if you'd like to have a look) was then submitted for the award, specifically based around the development of the system I mentioned I worked on in the second couple of weeks.
All initial correspondence with the co-ordinators (SO) was via email, and I only met them in person at the launch event, a visit during the placement, and a kind of 'award-giving' event a month after the placement had ended.
Generally, CREST Gold awards are for research placements - mine was kinda unique though there were definitely parallels with the other students' placements.
So yeah, let me know if you have any more questions or want me to send you the report