If you were to pop into Pure Freedoms unit and have a look at their system you would be surprised just how cheap their version is. It's totally different to the Posiden version. It's based on a Webasto unit which costs a fortune to source if you were to try building your own.
If I had the money I'd go for it.
The l5 type heater - does that need a pilot light burning all night to fire the frost stat up?
number 4 answers this.
BENEFITS OF PROTEUS
1. Flow sensitive, Saves fuel, Ideal for trigger users.
2. Instant hot water, fully temperature adjustable.
3. Only heats water used to save in running costs.
4. No pilot light for a safe system.
5. Auto cut off devices for safety.
6. Independant fuel source, no empty fuel tank at the end of the day!
7. Runs independent of battery, no danger of a flat battery.*
8. Low running and maintenance costs.
9. Small and light, (no payload worries, discreetly fits in the smallest of vehicles).
10. Retro fits any system.
11. Fully approved CE certified.
12. Eco friendly (see section on Flogas Offer Page).
13. Complies with ADR limited load regulations.
14. Easy to install. (Gas safe registered fitter required to connect LPG).
God I hope these systems are ok after me posting this stuff.....I am only copying and pasting off their site though.