wow that sounds awesome! cliff drop would be sick! unfortunately i have exams this week but i would have made plans to come up! ill look out for sick stuff like that a bit more in the future! i just wish MK got their shit together and put together a decent setup with some good hits....
last time i was there they had the baby slope with these little pathetic boxes and then had the really pro stuff like their massive rainbow, and the redbull street rail, which had the most ridiculous lip on to it, i only saw 3 people hit in the whole night... they need some more intermediate stuff that you can get some tricks lain down on
Anyway to the op there are loads of dry-slopes dotted about the country, i would say at least one in most major town/cities, but what you really need to do is look out for snowflex slopes, that stuff is better than the old school dentex matting, my local snowflex slope isn't very long though, so i won't recommend my slope as it only has a few jibs and some (very) small kickers.
havent been to many other slopes around the country, one dryslope is practically the same as next tbh, so i havent been to many, only 4 slopes i believe.... Warmwell in dorset (i think) is pretty good or so i am told, their slope is mostly snowflex, also Norfolk Ski Club have a really nice slope it seems from the pictures, i think it is a mixture of dentex and snowflex and they have several kickers and stuff (never been there but seeing as i only live about 70mins drive away i feel i should have given it a look!)
Have a look at skiing in the indoor places - they can be very expensive, and they usually only have a park setup one day a week, so watch out, they can be quite an experience!
Whatever you do just don't expect too much, and it will be an interesting experience!