Can you use the phil&teds cocoon travelfix booster with out the isofix installed?

Yes you can as the cocoon travelfix behaves the same way as a regular booster that has no anchor points. Retracting the isofix is required when just using the seat belt. Click here for instructions.

http://philandteds.com/nz/Products/Drive/cocoon-travelfix%E2%84%A2#.Up5kdNIW0hQ