Does the "including travel arrangements" part of your post mean that the scooter user hasn't got their own car? If so it will probably then be necessary to check on whether the scooter can be accommodated on trains. This spreadsheet shows the maximum dimensions for mobility scooters to be carried on the train services of different operators:
http://www.nationalrail.co.uk/All%20TOCs%20Scooter%20Carriage%20Policies.xlsx
(I used to work for a rail company. Smaller mobility scooters could be accommodated on all of our services but bigger ones couldn't. So, if the user plans on travelling by rail it's essential that the measurements of the scooter are known).
What type of place is the user seeking? An historic city? A coastal town? A place with lots of lively bars?
My first thought here might be Whitstable, which is an upmarket coastal town, served by rail, with lots of good bars and restaurants, largely flat and convenient for exploring places like Canterbury (which itself might also be a good place to stay). However such places might be of no interest if the scooter user lives in the far north of Scotland (meaning that it would involve a long and expensive journey to get to them) or if he/she actually lives in Kent anyway.
More information, please!