I've marked it and 142030 as "unit to be preserved", likewise with 142033 (which is marked as converted to other use) which apparently is being used by South Wales Police. List updated as of Wednesday 1st January 2020.
Red - withdrawn.
Orange - scrapped.
Yellow - converted to other use (does not include food tins or razor blades).
Green - modified for Passengers of Reduced Mobility.
Blue - in storage.
Purple - preserved.
Class 142
001 - Unit preserved. Due to move to the National Railway Museum in York.
002
003 - In storage at Barrow
004
005 - First to be withdrawn, now scrapped (updated as of 7th December 2019)
006
007 - In storage at Barrow
008 - Scrapped (Collided with a class 87 at Winsford in 1999).
009 - in storage at Gascoigne Wood
010
011
012 - at Landore TMD? being stripped of spare parts.
013
014
015 - in storage at Gascoigne Wood
016 - Scrapped, EMR Kingsbury
017 - in storage at Worksop
018
019 - in storage at Worksop
020 - in storage at Worksop
021 - was in storage at Botanic Gardens Hull, now at Gascoigne Wood.
022 - Scrapped, EMR Kingsbury
023
024
025 - Scrapped, EMR Kingsbury
026 - was in storage at Botanic Gardens Hull, now at Gascoigne Wood.
027 - in storage at Worksop
028 - In storage at Barrow
029 - Unit preserved at Chasewater Railway.
030 - Unit to be preserved at Chasewater Railway (Is this confirmed?)
031 - in storage at Holbeck, Leeds.
032
033 - Unit being used (as what?) by South Wales Police at Bridgend.
034 - In storage at Barrow
035
036 - Unit to be preserved at East Kent Railway, said unit is still in service at Northern.
037 - Scrapped, EMR Kingsbury
038 - in storage at Gascoigne Wood
039 - in storage at Gascoigne Wood
040 - In storage at Barrow
041
042 - in storage at Gascoigne Wood
043
044 - Scrapped, second class 142 unit to be dismantled at CF Booths (the first being 005).
045
046 - In storage at Barrow
047
048 - in storage at Gascoigne Wood
049 - in storage at Gascoigne Wood
050 - Scrapped, EMR Kingsbury?
051
052 - in storage at Worksop
053 - in storage at Gascoigne Wood
054
055
056 - In storage at Barrow
057 - in storage at Gascoigne Wood
058
059 - Scrapped (Collided with buffer stops at Liverpool Lime Street in 1991.)
060 - was in storage at Botanic Gardens Hull, now at Gascoigne Wood.
061
062
063
064 - Scrapped, EMR Kingsbury
065
066 - in storage at Gascoigne Wood
067
068
069
070
071
072
073
074
075
076
077
078
079 - at Landore TMD? being stripped of spare parts.
080
081
082
083
084 - in storage at Worksop
085
086 - at Canton, stripped of spare parts.
087
088 - Scrapped, EMR Kingsbury.
089
090
091 - in storage at Worksop
092 - in storage at Holbeck, Leeds
093 - Scrapped, EMR Kingsbury.
094
095
096 - Scrapped, EMR Kingsbury. The last of the class lost for good.
Class 143
601
602
603 - set to be preserved at the Swindon and Cricklade Railway
604
605
606
607
608
609
610
611
612
613 - Scrapped (Unit caught fire near Nailsea & Backwell in 2004).
614
615 - Scrapped (Unit caught fire in 2005).
616
617
618
619
620
621
622
623
624
625
Class 144 - All units stabled at Neville Hill.
001
002
003 - set to be preserved at the Great Central Railway at Ruddington.
004
005
006
007
008
009
010
011
012 - 144 Evolution has full PRM modifications.
013
014
015
016
017
018
019
020
021
022
023