Our previous LF-µSR measurements in natural type Ia single crystal diamond showed some evidence of the ionization of bond-centred muonium (MuBC) from around 1000K. This was further confirmed by a sudden increase in the population of the diamagnetic state. It would be interesting to repeat the previous measurement, concentrating on the important temperature region with additional data points and extending the maximum temperature measured from 1200K to 1300K, for a firm confirmation of the observed ionization of MuBC. This is significant as it would fix the gap level of the electronic state of bond centered muonium in diamond, and therefore have implications for bond-centered hydrogen in diamond (a material which is expected to have electronic applications). It would also constitute additional insight ito the dynamics of hydrogen in diamond.