Has issue to this day.

His baptism transcription from FindMyPast:

First name(s) William Basil Percy
Last name Fielding [sic, but mistranscribed]
Birth year - [sic]
Baptism year 1796
Baptism date 25 Mar 1796
Denomination Anglican
Place Shrewsbury, St Mary's
Father's first name(s) William Robert Lord Viscount
Mother's first name(s) Anne Catherine
Mother's last name -
Residence -
County Shropshire
Register type Baptism & Burial
Register date range 1775-1806
Archive reference P257/A/1/4
Page 110
Record set Shropshire Baptisms
Category Birth, Marriage, Death & Parish Records
Subcategory Parish Baptisms

The image of the register has this record:

“1795 ... March ...
“25 William Basil Percy son of William Robert Lord Viscount Feilding & Anne Catherine his wife born & baptized”

So it looks as if the birth was on the 25th March and as if the baptism may have been done at home rather than in the church, merely being entered in the Shrewsbury Register.  Some other entries for March include separate birth dates.
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In the 1851 census, all the birth places are given as Warwickshire which is clearly wrong and inexplicable.
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In the 1861 census:

(all Feilding surnames have been transcribed incorrectly)

(I have inserted the birth places from the enumerator’s sheet, note that his is given as Berwick House)

First name(s) Last name Relationship Marital status  Gender  Age  Birth year  Occupation  Birth place

William B P Fielding Head Widower Male 63 1798 Peer Of The Realm  Salop Berwick House
William Fielding Son Unmarried Male 25 1836 ...  Middlesex Bushey Park Hampton
Adelaide Fielding Daughter Unmarried Female 24  1837  -  London, St Georges
Katherine Fielding Daughter Unmarried Female -  -  -  London, St Georges
Susy Grant Visitor Unmarried Female 24  1837  -  Perthshire, ?ictgeaton

Address * Ref:
House name Newham...Hall
Street -
Parish Monks Kirby
City or borough -
County Leicestershire
Archive reference RG09
Piece number 2247
Folio 79
Page number 1

Ref construct:  RG09, piece 2247, folio 79, p. 1
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His death on FreeBMD:

Surname First name(s) Age District Vol Page
Deaths Sep 1865   (>99%)
Denbigh (Earl of)  William Basil Percy   Hampstead  1a  381
Fielding (Earl of Denbigh) William Basil Percy Hampstead 1a 381

and on FindMyPast:

Name: DENBIGH (EARL OF), William Basil Percy
Registration district: [?] Hampstead
County: London
Year of registration: 1865
Quarter of registration: Jul-Aug-Sep
Volume no: 1A
Page no: 381
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His MI at St Edith’s Church, Monks Kirby, Warwickshire:

“To the Glory of God and in Dear Memory of William Basil Percy 7th Earl of Denbigh who died June 25th 1865. (Bur Reg aged 69)  And of Mary Elizabeth Kitty his beloved wife who died Dec 16th 1842. (Bur Reg, aged 44) Erected by their eldest and twin children Rudolf and Mary”
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His Probate index:

Earl of DENBIGH and DESMOND, The right honourable William Basil Percy
Effects under £35,000
Resworn at the Stamp Office, Decr 1866, under £45,000
14 October [1865]
The Will with four Codicils of the Richt Honourable William Basil Percy Earl of Denbigh and Desmond late of Newnham Paddox in the Parish of Monks Kirby in the County of Warwick deceased who died 25 June 1865 at Oakhill in the Parish of St John Hampstead in the County of Middlesex was proved at Birmingham by the oaths of the Right Honourable Henry John Earl of Ducie of 1 Belgrave-square in the County of Middlesex and Henry Kingscote of 96 Eaton-place in the County of Middlesex Esquire two of the Executors.
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Argent on a fess Azure three lozenges Or

1619 Visitation of Warks, pub Harleian 1877, p, 11.

Their marriage transcription by FamilySearch:

First name(s) William Basil Percy
Last name Feilding
Marriage year 1822
Marriage date 08 May 1822
Marriage place Woodchester
Spouse's first name(s) Mary Elizth. Kitty
Spouse's last name Moreton
County Gloucestershire
Country England
Record set England Marriages 1538-1973
Category Birth, Marriage, Death & Parish Records
Subcategory Parish Marriages
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