So nobody could join the TF in the later stages of the War? They'd be shunted immediately into regular service?In the first year of the war, such disjointed service occurred. Those who were part of the TF could elect to be 'embodied for Regular service' for a determined period. At the end of that period of service, the individual could be released or volunteer for further embodied service.
Also, certainly during the first 2 years of the war, the TF man would be called forward to his Bn/Coy HQ, documented, and then either proceed through the system or (if he was in what later became a reserved occupation or offered exceptional personal circumstances as to preclude him from front line service), be sent home with a proviso for recall at a later date.