Please find attached a revised version of the manuscript. Note we have added three authors who were inadvertently omitted in the original. We have centred Fig. 1 and adjusted the references, so they are consistent with the journal style. In addition we have modified the text in response to the referees. A point by point response is included below. Sincerely, Andrew MacFarlane Ref 1 please check fig 4b: the temperature dependence of the Mössbauer hyperfine fields appears to be not smooth. I have no access to the Japanese data, so I cannot judge whether this is an artifact from reproduction or only from linear interpolations in the original data. I would recommend to show a smoothened interpolation. >> We originally showed the Mossbauer data as lines, rather than points, which are somewhat scattered. Now, instead, we show a smooth fitted curve. The text is modified to be consistent with this. Ref 2 Although the results presented in this paper are novel and interesting, their presentation seems a little chaotic and the study somewhat incomplete. The overall impression given is that this work was performed in a rush. >> This is a preliminary report of some new results - which we feel is appropriate for a conference paper. It is quite true that it was rushed. We have improved the manuscript to make it more coherent per the referee comments In section 4, it is stated that this study was performed in order to investigate the 'evolution of the magnetic phase with applied field'. A study of this would be interesting an would warrant publication, yet I am not convinced that the current study, performed in zero field and only one applied transverse field constitutes such a study. In fact, it is unclear as to what conclusions are drawn in this paper. >> Yes this is the first step to establish the zero and low field behavior. We now make this explicit. In the introduction it is stated that Sr3Fe2O7 is nonmetallic, yet reference 2 states that is metallic at 350K. This should be clarified. >> True - now fixed Likewise, the stoichiometry of the sample is referred to throughout as Sr3Fe2O7, but reference 1 implies that the oxygen content is less than this; again this should be clarified. The muSR data were collected from an oriented single crystal, yet from the subsequent analysis and discussion it is unclear why, as no discussion is made or conclusions drawn re. the inter and intra plane magnetism. >> This is the fully oxygenated end-member compound literally Sr3Fe2O7 - we make this more explicit in the revised version. The single crystal is important as the magnetic response is evidently anisotropic as shown in Fig. 1 Does figure 3 show the same data that was measured and shown in figure 2? This should be made clear, as well as any differences in the measurement. >> Yes it is with a different binning and time range - now this is explicit in the caption. It would be helpful to also see the oscillating data measured at 75K, and lower temperature to see that it is lost. >> We do not feel it is appropriate to include more data here that might preclude a future journal publication. In the discussion re. the oscillating signal it is stated that the damping is unusual for a conventional Neel state, yet these measurements were performed in the incommensurate phase. The precession frequencies measured are not stated at any point, but from figure 4, the frequency measured at 75K appears significantly higher than the 50MHz mentioned in the text. It would have been good for more points to have been measured in this region. >> We originally regarded the detailed magnetic structure as unknown. Though there is mounting evidence of an incommensurate helimagnetic structure. Now this seems clear, so we have removed mention of a conventional Neel state. It is unclear what information you feel has been gained from performing the transverse field measurements. As there are two distinct Fe ions shown by Mossbauer and different O environments (where the muon is likely to be situated), it is not remarkable that there are two frequencies. It would be good to have more discussion as to why these frequencies are so similar. >> The information is that there are two distinct muon environments that are not very different. This is likely related to the charge ordering, but it is not clear how. More measurements and calculations are needed to pursue this. In the summary, it is unclear why the average static field experienced by the muon has been determined by comparison with the Mossbauer data rather than by determining it from the precession frequency. >> We now include the measured field at the muon at 75 K. Because we cannot resolve the oscillations at low temperatures, we use the Mossbauer T dependence as an appropriate form to _extrapolate_ the T=0 muon precession frequency (which we also now quote). It appears that this study would benefit from measurement of much more data, which would enable some conclusions to be drawn. >> Data taking is underway and the results will be published in a follow up work to this preliminary report. This paper needs a careful proofread, as there are a number of typographical errors in the text. >> We have edited the paper carefully and hope that no errors remain.