We study a stochastic SIR model with two levels of mixing, namely a global level which is uniformly mixing, and a local level with two layers representing household and workplace contacts, respectively. First, we illustrate through simulations that a well calibrated, uniformly mixing SIR model yields a satisfying approximation of epidemic key characteristics. Second, we establish the large population convergence of the corresponding stochastic process. Convergence to the unique deterministic solution of a measure-valued equation is obtained. In the particular case of exponentially distributed infectious periods, we show that it is possible to further reduce the obtained deterministic limit, leading to a finite dimensional dynamical system capturing the epidemic dynamics.