Don't worry about a thing Stig, grab a hose, bucket, sponge, car shampoo... place your scoot under a shade (sun is bad news)...
1. No need the cover any part of the scoot, just hose to loosen dirt wiping with a rag at the same time... a little water pressure under the belly, under the fenders to remove those caked on stuff...
2. Then, with your bucket... foam in some shampoo and using a soft sponge, shampoo all parts of the scoot... from top to bottom...
3. Rinse and dry with a shammy... Done...
You can wax the panels afterwards...
I wash my scoot at least once a week... sometimes, I just hose-off the dirt while they are still fresh and let it be... Road dirt/sand contains salt that may corrode stuff on your scoot...
...or.... you can just bring your Like here and I'll ask someone to help....