
EarlyTimeA.dat and RelRates.dat contain the temperature dependences of early time average asymmetry, and stretched exponential relaxation rates for each dopant concentration, respectively, as described in the text. Each parameter is normalised for each concentration and the resulting values are plotted in Figs 1(a) and (b) in the manuscript.

00E13stretch.dat contains the fitted parameters obtained by fitting the stretched exponential relaxation function to the x=0 data measured at ISIS.
x00E13A0.dat contains the temperature dependence of the early time average asymmetry for x=0 data measured at ISIS, and x00E13A0.tab contains the results of fitting these average asymmetry values to the broadened step-function described in the text.
00G13osc3.dat contains the fitted parameters obtained by fitting the two-frequency oscillatory relaxation function to the x=0 data measured at SmuS. 

20G141freqStretch2.dat contains the fitted parameters obtained by fitting a single-frequency oscillatory relaxation function to the x=0.2 data measured at SmuS.

x67G142Lor2.dat, x75G142Lor.dat and x902Lor4.dat contain the fitted parameter values obtained by fitting relaxation functions comprising two exponential terms to data measured at SmuS for the x=0.67, 0.75 and 0.9 concentrations, respectively. This fitting procedure is explained in the supplemental information.

LSNOearlytavg.dat contains the temperature dependence of early time average asymmetry values for LSNO data measured at SmuS with x=0.5 (as described in the supplemental information), and LSNOearlytavg.tab contains the results of fitting these values to a broadened step-function. LSNOosc5.dat contains the fitted parameters obtained by fitting LSNO asymmetry data to an oscillatory relaxation function.