of cases spatially resolved data have been obtained, extending to projected radii of a few kpc.

Our dynamical analysis centred on these rotation velocities, $V_r$. In Paper I we collated the useful kinematic data on LBGs, selecting from the datasets of Pettini et al. (2001) and Erb et al. (2003), to define a sample of seven measured projected rotation velocities, $V_r$, as well as 32 velocity widths, characterised by the dispersion of the velocity profile $\sigma$. The galaxies for which rotation curves have been measured may not be representative of the LBG population: for example the luminosity profiles may be more extended than average. For this reason, a simple statistical analysis of the rotation velocities is not appropriate. Instead we were able to use the rotation velocities by making the assumption that the distribution of measured values of the dimensionless quantity $V_r/\sigma$ are representative. We then connected the rotation velocities, the velocity widths, and the $\Lambda$CDM predictions through the assumption of a linear relation $V_{c7}=\alpha\sigma$, where $V_{c7}$ is the circular velocity at a radius of 7kpc.[^2] The procedure was, firstly, to determine an observed value of $\alpha(obs)$ which, accounting for random orientations and inclinations (over cos($i$)), explained the observed distribution 