BBC DVD Problems

Some of the BBC DVD's which I have bought, from you and others, have cracks in the hub which are slowly getting larger and threatening to encroach into the data. Are you familiar with the problem? What, if anything, can I do to stop the cracks from spreading? Some websites that I have researched say to put super glue on the cracks and apply hub labels to strengthen the DVD's center. I don't want to change the DVD's balance and run the risk of having the DVD come apart inside the DVD Player. I have emailed your website directly but have never received a reply. Any advise or suggestions???

PS: The DVD's in question are only from the Doctor Who series. Other BBC DVDs/Series which I have purchased; UFO, Space 1999, Mr. Bean, Are you being served, Fawlty Towers, etc. are NOT affected.