Hi NannaLyn
I work for a building contractor, I have looked at replies and the following thoughts occur
With reguard to the new regs re paving you may need permission but listening to your comments about draining on to ground within your property may negate this, look at the diffrent paving manufacturers brochures for simple explanation
As other replies have said imprinted paving does require some resealing to maintain its looks ,its a new one to me about being slippery
Tarmac has very limited maintenace but make sure you have a base course and wearing course layers with a total thickness of about 65mm on a 150mm min well compacted hardcore(not just wearing course as provided by some of the travelling fraternity).
Paving blocks come in lots of different types and designs and i would agree with the costs of about 50 - 75 pounds a m2, these require very limited maintenance and if your drive sinks then repairs are simple to carry out as is replacing blocks that have oil spills on them
The are porous systems of paving blocks but these require a ground porosity test to see if your ground will absorb the rainwater, if your ground does not then there is the danger of your paving becomming soft and spongy during wet spells
There also plastic and concrete grid types of surface, some of these are laid on sand on a hardcore base for regular use or laid on sand on earth for occasional or limited movement parking these give the effect of a lawn and this of course will require cutting
Which ever system you use the most important advice is to use a competent contractor preferably someone who comes recommended or whose work can be checked on with their previous customers, beware of old reccomendations.
Hope this helps
Alb