From Watford Junction train to Euston Underground Station, Tube to Finsbury Park Underground Station, then Tube to Arnos Grove Underground Station. 38 min £9. From Watford, Beechen Grove line 142 bus to Edgware then line 251 bus to Arnos Grove, Betstyle Road Arnos Grove. 1 h 31 min £3. From Watford taxi to New Southgate. 21 min £73. From Watford drive to New Southgate. 21 min £3.