We had a request for a list of sportives.  A list of the common, local(ish) ones is below, but there are lots more further afield (see links at the bottom).
 If you are thinking of riding one and want some company, why not post to the forum and see if you can   get  a group  together.

Cambridgeshire Classic
Peterborough
Date: Sunday, March 1 2020
Distance: 34, 52, 70 miles
https://www.ukcyclingevents.co.uk/events/cambridgeshire-classic-cycling-sportive/

Ware’s Cambridge
Ware
Date:  15th of March 2020
Distance:  30, 50, 80 miles
http://www.sportiveuk.co.uk/

Suffolk Spring Classic
Newmarket
Date: March 22 2020
Distance: 40,75 miles
https://www.ukcyclingevents.co.uk/events/cambridgeshire-classic-cycling-sportive/

Richardsons Rumble
St Ives, Cambs
Date: April 19
Distance: 38,67,107 miles
https://www.wheelsinwheels.com/Richardsons_Rumble_Cycling_Sportive_St_Ives_UK.php

Cambridge 100/60/35
Histon
Date: May 3
Distance: 35,60,100 miles
https://www.bike-events.co.uk/Ride.aspx?id=683

London to Cambridge
London (Bus from Cambridge)
Date: 26th July
Distance: 60  miles
https://www.bike-events.co.uk/CalendarEntry.aspx?id=7958

Tour of Cambridgeshire
Peterborough
Date:  7th June
Distance:  70, 100 miles
https://www.golazocycling.com/Tour_of_Cambridgeshire/Tour_of_Cambridgeshire_Cycling_Festival_UK.php


Evans Cambridge Ride-it
Wimpole Hall
Date: 12th July
Distance: 37,64,89 miles
https://www.evanscycles.com/evans-cycles-cambridge-road-sportive-sunday-12th-july-2020-EV374086

Hertfordshire 100
Hatfield
Date: 30th August
Distance: 32,64,100 miles
http://www.sportiveuk.co.uk/hertfordshire-100/ 


Lots more can be found online. e.g.

https://www.sportive.com/sportive-calendar/uk/east

https://www.cyclingweekly.com/news/latest-news/cyclosportive-cycling-events-calendar-366182

https://www.britishcycling.org.uk/events?search_type=upcomingevents&zuv_bc_event_filter_id=5