Boost switch for Halstead Central Heating boiler

[planenut]

I wish to install a one hour boost switch to control a Halstead Finest Gold Combi boiler outside of the clock control times. I have bought a Horstmann Electrisaver E15 which appears to supply power on the output side at full voltage. I wish to bridge the two "switched" wires to the control panel clock/timer to have the ability for the overide action to be cancelled after an hour.
Having waited for a while for an answer from Halstead, I wondered if anybody knew if this application of the E15 in this position is correct? or the wrong choice.
Hoping for a tolerant reply.

 

[gas4you]

Wht not just fit an external single channel programmer/timer with a 1 hour boost button built in

 

[planenut]

Wht not just fit an external single channel programmer/timer with a 1 hour boost button built in

I want to restrict the access to the boost button, therefore leaving the clock secure? most timers, logically have the clock and boost on the same unit.
Thanks.