the pressure profile ( Fig.\[Pressure\]) , $\beta$ and $r_{cx}$ are the parameters of the $\beta$-model found by fitting to the surface brightness profile, and $n_p$ and $n_e$ are the proton and electron number densities at a given radius.

We then integrate equation \[betamodel1\] out to $r=245$ kpc (160 arcsec) to determine the total number of particles in our sphere of influence, $N_{\rm tot} = 3.24^{+0.44}_{-1.07}\times10^{68}$; multiplying this by ${3\over 2}kT$ (where $T$ is the temperature of the gas in region 1 as found in the spectral extraction) gives the thermal energy stored in the region, $9.17_{-2.93}^{+0.89}\times10^{52}$ J or $9.17_{-2.93}^{+0.89}\times10^{59}$ erg. Effectively, this calculation also gives us the heat capacity of the gas in the region, on the assumption that all work done on the gas remains present as excess heat, $C = {3\over 2}kN_{\rm tot}$. Using this, we find that the work done by the AGN (as calculated above) should increase the temperature of the inner region by 0.39 keV. This is very consistent with the observed higher temperature in the centre of the group. There are several important caveats in doing this simple comparison: firstly, the estimate of $PV$ work done is probably not accurate to within better than 