Thermostat 900 thunderbird

I've just fitted a new thermostat as per the instructions of the Haynes manual put the front and the rear housing together but had to compress the thermostat to fit together it's round the right way and in the grooves as per instructions is this right as there is nothing stated in the manual about being spring loaded and difficult to fit .. I'm thinking have I got the right thermostat as it was as per the world of triumph parts list I'm a little confused now it's compressed is it in the open position .... The mysteries of thermostats right up there with the mysteries of dry cleaning clothes ... I am geninely confused please help

 

took it all apart last night compared size to the old one and its the same size.. tried to put it back in and will not shut the housing without compressing so i removed the stat completely ran the bike for 40 miles run like a dream probably not ideal but the temp was fine as it was a nice evening im at a loss completely why it doesn't fit i placed the old one back in and that didn't fit now ive followed all the instructions diagrams etc on the lugs and the nipple on the top inserted ..... its a puzzle