I have just done a upgrade on my mate's Severn class lifeboat. He was running a 2.4 set-up for quite some time but we where getting interference from the new 2.4 transmitters. He is now running with a 5.8Ghz system which we got from
http://www.firstpersonview.co.uk/ the transmitter is of the 25mw power which is the limit for the UK without a licence. It works very well with a range of about 350 Meters.
You need to be aware that a lot of the stuff on ebay and from over seas has a higher power output than is allowed in the UK without a licence.
If you want to record the pictures look for an MP4 recorder you can get them of ebay for about £45