Take care, there are so many cowboys out there doing block paving which looks good once it's done but due to lack of proper foundations susidence is imminent. Quite a lot of these firms sub contract and a lot of people they sub contract to are Irish travellers.
Avoid firms with freephone or mobile numbers because if things go wrong you will not be able to contact them.
Get a quote from a reputable local builders and if things do go wrong you know who to contact and where to contact them.
Whoever you use ask for an address near you where you can have a look at the finished result, not a recent job but one completed several months ago. A good time to look is when it's raining, you can see where the water is draining (not towards the house) and you can look for puddles where the blocks have sunk.
Hope I didn't put you off too much. Block paving if correctly done is a good idea, pleasant to look at , walk on and almost maintenance free.
Good luck with it.