Potty Training childminders

[hinchlic]

My daughters (twins) are 2 and 9 months (not sure of the days, hours and seconds lol).
Anyway we have started potty training, and all is going well. I have 2 older children also , now 10 and 13, Both potty trained well at around the same age as twins 2 1/2 year mark but was looked after by mum so could run round naked etc, take self to potty and both went to state nursery at 3 trained no trouble. The twins are looked after by a childminder, potty training all going well at home, take self to potty, ask to go occasionally, take underwear down etc, do number 1's and 2's. But one of the twins is refusing to use potty nearly all day at childminders? then finally wets self??? Hasn't the facility to take self to toilet at the childminders as has to go through various doors that aren't left open as childminder has babies there?. Won't ask the childminder??? (shy), .Is getting asked by childminder to go regularly, will go potty with sister but says 'no' ???? I think the childminder needs to be a bit more creative as looks like my twin wants to be in control. But moans about not having time as has other children???, was saying at first wanted to use pull ups but I point blank refused. Has anyone any suggestions on what we could try?.