Knowledge of how the Antarctic Ice Sheet (AIS) has varied in response to past climates can inform the prediction of future AIS behaviour. Water stable isotope records from Antarctic ice cores traditionally provide information on past temperature changes. However, these reconstructions neglect changes in atmospheric circulation, which can be induced by elevation changes. Here, we simulate an ensemble of idealised AIS elevation change scenarios using the isotope-enabled HadCM3 climate model during the Last Interglacial period (LIG). Our ensemble is used to investigate the isotope-elevation relationship. Changing AIS elevations linearly modify the response in surface air temperature, as precipitation and $\delta^{18}$O. Especially, we observe $\delta^{18}$O decrease with the AIS elevation, with higher slopes on the coast compared to the plateau, reflecting different processes. We note that the effect of sea-ice induced by AIS changes is small. These results help to isolate the effect of AIS changes on the LIG $\delta^{18}$O signals.