Hi and well done on your losses, you must be very proud
I never had problems with plateaus but I believe an couple of ways to get through are via calorie cycling- basically vary th amount you eat each day by working out your calorie allowance for the week and then rather than sticking to say 1500 cals everyday, have 1500 one day, 1200 the next,1700 the day after that and so on. As long as by the end of the week you have eaten your weekly calorie allowance all is good. Another way would be to have a bigger breakfast than normal but then have a smaller lunch, shake things up a bit and vary what you eat.
Good luck, Sue
Edited to say also give the exercise routine a shake up, try varying what you are doing and the intencity.
How many cals a day are you eating?