aaaahhhh....guns on UK combat aircraft, and lack thereof....
GR7 was going to get a 25mm version of the Aden 30mm, but the project got canned in late 90s due to problems with getting gun and pod to work together. Would have been a good weapon, high velocity and very high rate of fire, but it got cancelled along with the Typhoon cannon at the same time - Air Staffs had decided that guns were 'not a viable weapon' (thsi analysis was built around air to air scenarios). Doesn't look so good a decision now, but at the time, it was made in good faith.
IMHO, we will see a comeback for guns as long as we are in the sort of war Afghanistan presents. The debate over guns on the JSF in the States was effectively closed the day the USAF used F-16 guns again in anger against ground targets in Iraq. JSF CTOL variant has a 25mm gatling built in, STOVL has a centreline podded version of the same gun.