Garden drainage is normally required if there is a flooding issue or if the soil is not of the correct type, but installing land drainage is an art and if not done correctly will make matters worse, so for instance the correct size of shingle must be used , a porous membrane should be used to ensure the perforated pipe work does not get blocked in the future.

So make sure who ever does your land drainage they know what they are doing.

This is a herringbone design and commonly used when dealing with a water logged garden. 

  DRAINAGE EXPERTS LTD: FOR ALL YOUR LAND DRAINAGE REQUIREMENTS.

Some useful info Land Drainage Act 1994 

AREAS WE COVER

SW LONDON,SE LONDON,CROYDON,LEWISHAM,SYDENHAM,CRYSTAL PALACE,PUTNEY,KENSINGTON,KENNINGTON,CHELSEA,WANDSWORTH,

WIMBLEDON,MITCHAM,PURLEY,CARSHALTON,EARLS COURT,TOOTING,STREATHAM,

BRIXTON, LEE GREEN,DULWICH,WOOLICH,CHARLTON,BECKENHAM,DOWNHAM,

GROVE PARK,KINGSTON,LEE,ELTHAM,ELEPHANT & CASTLE,CAMBERWELL,CITY,

ERITH,CRAYFORD,DARTFORD,WILMINGTON,SWANLEY,FARNINGHAM,

EYNSFORD,SHOREHAM,BADGERSMOUNT,

PRATTSBOTTOM,FARNBOROUGH,ORPINGTON,CROCKENHILL,ST.PAULS CRAY,STMARYS CRAY,

FOOTS CRAY,SIDCUP,OLD BEXLEY,BEXLEY,BEXLEY HEATH,WELLING,ABBEY WOOD,BELVADERE,THAMESMEAD,WOOLWICH,CHARLTON,PLUMSTEAD,

KIDBROOKE,ELTHAM,BLACKFEN,

NEW ELTHAM,MOTTINGHAM,CHISLEHURST,PETSWOOD,KESTON,NEW ADDINGTON,

ADDINGTON,WEST WICKHAM

HAYES,BECKINGHAM,BROMLEY,CATFORD,SYDENHAM,GROVE PARK ,LEE,LEWISHAM,

BLACKHEATH,GREENWICH,

DEPTFORD,BERMONDSEY,LAMBETH,CAMBERWELL,WEST NORWOOD,DULWICH,CRYSTAL PALACE,

PENGE,SOUTH NORWOOD,THORNTON HEATH,ADDISCOMBE,CROYDON,PURLEY,

COULSDON,SURREY,WALLINGTON,BEDDINGTON,

MITCHAM,STREATHAM,BRIXTON,CLAPHAM,

,WESTMINSTER,KENSINGTON,KNIGHTSBRIDGE,CHELSEA,HAMMERSMITH,BARNES,

FULHAM,BATTERSEA,PUTNEY,WANDSWORTH,

LONDON BRIDGE,TOOTING,WIMBLEDON,MERTON,MORDEN,NEW MALDEN,

CARSHALTON,SUTTON,EWELL,

CHEAM,WORCESTER PARK,BRENTFORD,ISLEWORTH,RICHMOND,SHEEN,KEW,

ROEHAMPTON,TWICKENHAM,HAM,

TEDDINGTON,KINGSTON UPON THAMES,HAMPTON WICK,THAMES DITTON,LONG DITTON,

TOLWORTH,CHESSINGTON,

CLAYGATE,ESHER,EAST MOLESLEY,HAMPTON,HOUNSLOW,HESTON,SOUTHALL,

WESTDRAYTON,HARLINGTON,

HEATHROW,HATTON,HACKNEY,CRANFORD,STANWELL MOOR,ASHFORD,FELTHAM,

SUNBURY,SHEPPERTON,WALTON ON THAMES,WEYBRIDGE,CHERTSEY,STAINES,

COULSDON,REDHILL,GATWICK,

CRAWLEY,HORLEY,REIGATE,DORKING

SW LONDON,SE LONDON,N LONDON,NW LONDON.

AND MANY OTHER AREAS GIVE DRAINAGE EXPERTS A CALL.

DRAIN CCTV SURVEY, DRAIN TRACING, DRAIN JETTING, DRAIN MAINTENANCE & DRAIN REPAIRS.

LAND DRAINAGE EXPERTS