You can drill if you want but if there are stem or base leaks on any of the solenoids then drilling it will not stop them. Give it a go you may get lucky.
I am looking for £140 for the v-block that is posted as well.
Kurt
I have an as new valve block for sale if you need one, save yourself the hassle and tears. Up to you but drilling into a valve block does not always end well. Any swarf in the ports and you will have major leaks on the solenoids and return valves.
Save the stress and burden and swearing and depression. I have a valve block for sale that is Virtually as new :banana::banana: #problemsolved :D:D:D:D