Fortyodd
I may be old but definitely not fruity.
T1 to T2 CPDS is old hat I know. The issue is CDS to CPDS. I was told by ECD 6 months ago it wouldn't happen. The advice of this conversion being available is fairly recent.
The issue is CDS 1 of any flavour cannot be modded to a 2 without change to CPDS.
Was your machine originally CDS?