There seem to be alot of training opportunities in Surrey and Kent.
Google your county or town + "dormouse training".
In the meantime, put your training records in order.
Track down the date of every training session or box making, monitoring, handling and photography you have done.
Make it into a chart so it looks professional:
headings would be:
date, location, operations carried out, supervised by, and other comments.
Include making, siting of and checking boxes, safe way of emptying them, and equipment used, safe handling, sexing, knowledge of dormouse ecology, feeding, breeding, etc. Say whether you observed or carried out activities, and how many dormice or nest boxes were involved.
This will be useful when applying for a licence, but also to let any new trainer know how knowledgeable you are. If you show any photos they need to say "taken under supervision of licence holder" or similar.
You also need to be familiar with the dormouse conservation handbook which is available online.
IN29 - Dormouse Conservation Handbook
If you haven't looked at the licence application, you can do it online
http://naturalengland.etraderstores....glandShop/IN29
Regarding the references, I would have thought that as long as one referee has seen you do all operations you are applying for, then the other could give you a reference for the operations you have done with them.
The link to the PTES is probably your best bet, so email your experience to them too when you write.
There's nothing to stop you putting boxes up (I presume you have to get permission from the landowner though), but checking will need to wait until you are accompanied.
Dormouse Monitor Greenboot