As for cleared to land when one aircraft is still to vacate... well, it does include a certain distance that not many regional aerodromes in the UK could accommodate. I'm out of touch but I think it says the preceeding aircraft must be 2500m further along the runway and in continuous motion? However, remember that this is used elsewhere in Europe... as is the 2.5NM on final approach within the last 10 miles.
Again, true, but the cleared to land with one to vacate (reduced runway separation) has only recently been formalised and incorporated into ICAO documents. LL was doing it long ago. And not every airport is handling aircraft the size of those at LL, so the distances involved might be accommodated on the runway length available. But the principle was that LL was in some way able to use these procedures - and again I think CC was similarly authorised - whilst other airports were not.
BTW, on the wake vortex categories (or wake turbulence as we're now supposed to call it on the RTF), I think that even for the categories that are used by ICAO the weights used as the cut-off point in the UK are different.