There are various options to get to Blanzay including driving from the Brittany/Normandy ferry ports with Caen Ouistreham being the nearest (4.5 hours) or Dieppe (5.5 hours).
Those wishing to take the train will need to get the TGV from Paris to Poitiers (only 1hr 20mins). Poitiers is well served by car rental offices near the railway station. It is then a 40 minute drive via the N10 to Junction 41 to take the D98 to Blanzay. It is possible to get a regional train from Poitiers to Saint-Saviol but there is no car hire at Saint-Saviol.
There are a choice of flights from the UK to Poitiers or Limoges (Ryanair) or La Rochelle or Bordeaux (EasyJet) but you will need to check with the relevant airlines for further details.