Have just done factory reset on my iPad endeavouring to delete BTYahoo mail from my much preferred BT mail. Thought I had solved my problem but BTYahoo mail did another take over of the iPad in less than a day. After a long long wait was able to contact BT and my first advisor. Was told BTwas changing over members to BTmail gradually, but got no answer as to why it was taking years. Was passed on to a technical adviser who did not actually u derstand what a factory reset was. Then got my third technical advisor whoactually admitted BT mail and BTYahoo mail had a bit of a problem co existing together. Passed on again to be told she had not heard of this problem and then passed me on to my fourth advisor who told me I should not have to leave BT over this simple problem,but did not have a solution to offer. I finally signed out after nearly one and three quarter hours. I did actually sign off by asking if all the lines men who used to string copper wires to telegraph posts re-trained as BT internet technicians. Very unfair of me, but I was by this time somewhat impatient. After the scandle over Yahoo security perhaps BT might want to review changing all members sometime, if ever.