2025 events: 

March:
Hospice2Hospice Half Marathon

April:
Finish Cancer Treatment
Southampton Half Marathon
London Marathon

September:
Berlin Marathon
Nice by UTMB 50k

October:
Amsterdam Half Marathon

December:
Malaga Half Marathon

So far, I have had a go at these races. Ordered by distance then dates (first run) and then times where remembered:

10 x Marathons

9 x Ultramarathons completions (current batting average: 9 finish v 6 DNF)

South Downs Way 100 miles 2017 (DNF), 2018 (22:48:22)

North Downs Way 100 miles 2016 (29:14:16)

Trail Verbier Saint Bernard 140k 2023 (DNF)

Madeira Island Ultra Trail 2019 115k (DNF)

London2Brighton Challenge 100k 2015 (13:35:10), 2022 (16:54:16)

Channel Islands 100k 2019 (DNF)

Round The Rock 48 miles 2021 (10:59:57)

CTS Dorset Ultra Plus 2015 46 miles (DNF), 2017 (11:52:10)

Guernsey Ultra 36 2019 (7:42:40)

Nice by UTMB 55k 2025 (11:02:25)

CTS Dorset Ultra 2016 33 miles (DNF)

Hurtwood 50k 2023 (6:18:24)

Royal Parks Ultra 50k 2013 (5:39:27)

Valencia Marathon 2018 (3:55:25)

Chicago Marathon 2017 (3:40:49)

Southampton Marathon 2017 (3:53:21), 2019(3:38:28)

Frankfurt Marathon 2016 (3:57:52)

Paris Marathon 2016 (4:10:37)

Berlin Marathon 2025 (4:37:11)

Stockholm Marathon 2014 (5:40:46)

London Marathon 2010 (5:12:22) 2025 (5:05:35)

Southampton Half Marathon 2023 (1:45:34)

New Forest Half Marathon 2008 (1:55:00), 2015 (1:36:04)

Brighton Half Marathon 2013, 2015 (1:51:00)

Royal Parks Half Marathon 2008 (1:53:00)

Bacchus Half Marathon 2014 (3:07:00)

31 different parkrun events, 23 letters and 9 countries (technically not a race):

Albert, Amsterdamse Bos (Netherlands), Brighton & Hove, Byxbee, Clapham Common, Dalby Forest, Dungloe (Ireland), Eastleigh, Fulham Palace, Greenpoint (South Africa), Hove Promenade, Itchen Valley Country Park, Jersey (Jersey), Keswick, Milano Nord (Italy), Lee-On-The-Solent, Mile End (PB 00:20:24), Moors Valley Country Park, Netley Abbey, Poolbeg (Ireland), Old Deer Park, Preston Park, Princes Park, Richmond, Southampton, Tees Barrage, University of Stirling, Victoria Docks, Wimbledon Common, Winchester, and Zielony Jar (Poland).

Canaccord Corporate 5k Cup x 2 winner (PB 00:19:34)

RockNRoad Beer Mile 2022 (0:08:05)

Canaccord Genuity Guernsey Inter-Firm Mile Relay (0:05:43)

Swimrun

BRECA Jersey 2019 (8:30:39)

Triathlon

Jersey Triathlon 2018 (2:58:25)

Hever Castle Olympic Triathlon 2015 (3:10:01)