found this on ebay (http://www.ebay.co.uk/itm/281573370486):

has a much better flow rate of 500ml/min quite good for a peristaltic pump

it seems that diaphragm pumps are much faster, but there are some issues with cleaning, as shown below, the tube can be replaced easily:

this is fantastic for this kind of application, but unfortunately, at £22.99 a pop, that would take the cost of a reagent 'module' up to £50ish

originally had thought one pump, controller and light per reagent in a module, chain-able using I2C so you can add as many as you like. this is great, but turns out might be expensive.

need to find another way of doing this i think.