Please send blood test results for FBC, ferritin, transferrin saturations and serum iron. If ferritin is below 50mcg/L, consider starting oral iron.
For further guidance please see Allen RP, Picchietti DL, Auerbach M, et al. Evidence-based and consensus clinical practice guidelines for the iron treatment of restless legs syndrome/Willis-Ekbom disease in adults and children: an IRLSSG task force report. Sleep Med. 2018;41:27-44. doi:10.1016/j.sleep.2017.11.1126