“At ISD doesn't DA transfer to the MoD IPT”
The transfer that occurs around ISD is control of responsibility for the design. i.e. It goes from “Under Contractor Control” to “Under Ministry Control”. It is a sad fact of life that the MoD seldom subsequently maintains full control of the design, which is seen as an easy target for the beancounters on the grounds that the money doesn’t produce anything tangible, like stock on a shelf. It maintains safety (as opposed to delivering it in the first place), a concept they don’t understand.
While there are exceptions, for example the MoD is DA for some engines, the contractor is usually appointed as the Design Authority or Design Custodian, depending largely on where the Intellectual Property Rights lie, and whether the equipment is of foreign origin or not.
The MoD is also DA for Service Engineered Mods not subject to a superceding cover mod. Various Defence Committees have recommended that DA (they don’t understand the Design Custodian concept) be competed at regular intervals, which completely ignores the simple fact that what sustains the entire process is expertise and continuity at the contractor. Similarly, managing the maintenance of the build standard is a lost art in MoD. If you were to study the reasons why many modifications programmes are years late (e.g. BOWMAN platform conversions) the common denominator is this failure of process and procedure.
There is little or no understanding of this in most IPTs, despite there being perfectly good Defence Standards written by people who do this for fun. Many think it a complete waste of money. Many DECs never even ask for funds in the first place, so taking the decision away from IPTs. It’s a false economy – investing in something so fundamental is the key enabler to upgrade programmes, of which there are more and more as we don’t have funds to replace kit.