Thanks sooo much Matt, that information is great as it puts things into perspective for me.  I'm so glad I came across this site!

Thanks for your replies, Matt and Catlyst.   The defense service housing maintenance charge is now 16.5% and they say annual rental yield is 3.58%, I don't know if this is a good rate or not as I have nothing to compare it to. Do you know what a reasonable rental yield percentage should be?  Thanks Sharon