Superstrike Ltd v Rodrigues

Tenancy Deposits

I have just read your deposits in turmoil artical on pages 16-17 of the latest RPI mag.
I have 9 properties I let out and use RLA as my landlord bible and have thus far never had any major issues. I am somewhat confused now as to how to make your AST's fully compliant with specific regard to tenancy deposits. I always use the none deposit guard tenancy agreement and am fully compliant through the DPS scheme and always supply the prescibed info. I also always serve a section 21b during the term of the tenancy agreement after the deposit is lodged and allow my tenancy agreements to go periodic. My questions are thus:
Do I now have to serve the DPS prescibed info again when it goes periodic?
If so does this invalidate the running S21b and will I then have to serve a new S21a and let it run for an extra 2 months into the periodic before I can enforce it through the courts?
I am considering using the DG ast for the deposit in the future, will you/be able to alter the DG and none DG tenancy agreement in the future to negate the need to serve the prescibed info again at the end of the fixed term and to enable any running S21b to be continuous and remain in force when the ast goes periodic?(ie a change back to a contractual continuation based ast) If you only changed to periodic for DG reasons then surely the none DG ast would be better set up as a CC ast.

Thanks in advance.