Sample size is based on the existing literature & on our experiences at Phase II. The estimated standard deviation of the primary outcome measure is 2.5. In order to detect a 2-point difference in mean outcome between groups (equivalent to 0.8sd effect size) with 80% power using a t-test at the 5% level of significance, it will be necessary to recruit 26 patients per arm per disease group (trial) followed up to provide an outcome, which will now be at an earlier time point to minimize attrition. By adjusting for the baseline of the primary outcome measure in the analysis using analysis of covariance we anticipate an improvement in the precision of the estimated intervention effect. We also anticipate an improvement from the use in the trial of the NRS measure rather than the more highly variable VAS version from the pilot used in this sample size calculation. Therefore we propose to recruit 120 patients, 60 per disease group to ensure adequate power, effect size and allowance for attrition.