There are two the old start finnish straight and into Brooklands. But only one detection zone again. 


ESPNF1:
At Silverstone, however, the system will revert to just the one zone as was common earlier in the season, with the zone being positioned from just after turn four to include the turn five kink and the Wellington straight on the run down to Brooklands, which will be turn six on the new track layout. The FIA had considered having two zones at Silverstone, with the second being on the old pit straight after Woodcote, but have now decided one will be sufficient.
The detection point for the zone will be before Village, the new turn three.