WIMBLEDON - I could find nothing on discounted prices but here is the link to the website regarding disabled access. I have messaged them requesting the relevant information when they get back to me I will let you know.
http://www.wimbledon.com/en_GB/atoz/accessbility.html
NEWCASTLE FOOTBALL CLUB
Newcastle United football club disabled info
http://www.nufc.co.uk/page/Club/DisabledInformation
SUNDERLAND FOOTBALL CLUB
Information on all accessibility available at the club plus how to claim discounted tickets go to
AINTREE RACECOURSE.
They offer concessions for people over 60 and students but not for carers.
However, information about accessibility for racecourse bars etc can be found here
https://www.thejockeyclub.co.uk/aintree/visitor-info/physical-accessibility/