Looks like your grandfather served first in the militia and then joined the regular army. It does not shown how long he enlisted for or when he was discharged.

British Army Service Records 1760-1915
Name ALFRED PIGGOTT
Birth year 1880
Birth parish PLAISTOW
Birth town PLAISTON
Birth county ESSEX
Birth country ENGLAND
Service number 7118
Rank -
Regiment -
Document Type Attestation
Attestation year 4 May 1898
Attestation age years 18 months 9
Attestation Corps 4TH
Attestation service number 7118
Series WO96 militia service records 1806-1915
Box 774
Box Record Number 286
Record set British Army Service Records 1760-1915
Category Military, armed forces & conflict
Subcategory Regimental & service records
Collections from Great Britain



British Army Service Records 1760-1915
Name ALFRED PIGGOTT
Birth year 1880
Birth parish PLAISTOW
Birth town PLAISTOW
Birth county ESSEX
Birth country ENGLAND
Service number 28175
Rank -
Regiment Royal Artillery
Document Type Attestation
Attestation 7 June 1898
Attestation age years 18 months 2
Attestation Corps Royal Artillery
Attestation service number 28175
Discharge Corps Royal Artillery
Series WO97 chelsea pensioners british army service records 1760-1913
Box 3655
Box Record Number 104
Record set British Army Service Records 1760-1915
Category Military, armed forces & conflict
Subcategory Regimental & service records
Collections from Great Britain

Could not find a death for 1934 but found this;

New Zealand, Death Index
Name: Alfred Piggott
Death Date: Oct-Nov-Dec 1937
Registration Place: New Brighton, Canterbury, New Zealand
Folio Number: 4165


Marriage:
Name: Alfred Piggott
Gender: Male
Age: 23
Birth Date: 1879
Marriage Date: 1 Mar 1902
Marriage Place: Canning-Town, Essex, England
Father: Stephen Piggott
Spouse: Jessie Selina Trowers
FHL Film Number: 1471944
Reference ID: it 5, p 61
Jessie's father was Thomas Trowers

Do you know if Jessie travelled with him to New Zealand ?

Christchurch City Council Cemeteries Database
Result Detail
Surname: Piggott
First name(s): Alfred
Date of death: Monday, 13 December 1937
Cemetery: Bromley
Date of burial: Wednesday, 15 December 1937
Block number: 31
Plot number: 122
Age:
Address: 31 Mathiesons Road, ChCh
Occupation: Labourer
Place of birth: England

Thankyou so much for this info, no jessie didnt go with him I found records where she remarried, but couldnt find any divorce records but guess that must have happened.we have the info of his relationship with my grandmother ( mother of my father, they didnt marry, she died when my dad was 4, my grandfather then went on to marry twice.and those were his death records I had date wrong. Would really like to discover when he arrived in nz.we had stories from my father he worked his passage out on the ship ionic, just trying to fill in the details of family history. It appears my grandfather was a bit of a ratbag and had served time in prison in nz for fraud, very interesting history. Thankyou for your help

not sure if this is your Alfred:

Liverpool, England, Crew Lists
Name: A Piggott
Age: 24
Birth Year: abt 1879
Birth Place: London
Event Date: 1903
Port of Registry: Liverpool, Lancashire, England
Ship Name: Orita
Official Number: 118010
Reference Number: 387CRE/653

Sounds very likely thank you for your help