Happily, Eursotar can carry wheelcahir users and have a special fare:
http://www.eurostar.com/UK/uk/leisure/travel_information/before_you_go/special_travel_needs.jsp
If you email them then you will be able to bring up any specific needs or concerns.
http://www.eurostar.com/UK/uk/leisure/travel_information/before_you_go/special_travel_needs.jsp
If you email them then you will be able to bring up any specific needs or concerns.