not sure about mentioning previous refusal, but you better make sure the reasons for refusal are covered as best you can or you'll get another refusal.
buying the tickets in advance i dont think would help, for the reason you've mentioned - you could get a refund and also it doesn't prove she would go back,
sure money in her account could help, but i wouldn't send a bank statement that shows money going in her account - they ECO people are not complete,y
, they know all the tricks
but if your going to sponsor her whats the point of you sending her money.. ?
yes a shorter period like 4wks might help as oyu've been refused once, and then next time increase the time she stays here here,
not sure if i sent you this link b4, might give you a few ideas...
http://www.londonelegance.com/transp...tionLetter.pdf