The aim of this study is to see whether the success rates for this technique can be improved. One method "catheter directed foam sclerotherapy" involves the delivery of the foam through a catheter (a long very thin tube), so that large lengths of vein can be treated through a single hole. The final method "ClariVein" again uses a catheter; but this time the catheter has a small wire on the end which spins around inside the vein; similar to an edge strimmer in the garden; except it irritates the vein: rather than cutting it. This irritation makes the vein more susceptible to the drug which can again be applied directly to the vein wall whilst it is still active. Early results show that this final method is very successful; however the equipment is more expensive than for the other two.