Beautiful set by the way!!!!!You have a dessert set and serving platter here and those are dessert plates. There were used for tea time...so for sweets or sandwiches. Very stylish and "in" to have a set at the time these were made.
W R Midwinter LTD is the full name. Here is the list on Replacements LTD of Midwinters "known" patterns. Just open each one and hopefully you will find you pattern/value. NOTE: This is insured value and NOT what you would get as an individual selling.
Burslem is the town in England that these were made in.
The squiggle on the plates is an identifying mark for the factory. It could be for the factory line, factory artist, etc. Each factory has their own way of helping to track items. Unfortunately, not all information is available about this for so many manufacturers over the years/centuries.