Bit late to the party on this one.
There shouldn't need to be any work done at the cab at all. Any jumpering will be on the MDF in the exchange. The fact that your phone had gone over to BT suggests this part has been done correctly.
As far as the DSL side of things then AIUI, once the FTTC tie pair is installed, any port mapping at the cab is supposed to be done remotely. Change of ISP does not require a visit to the cab as the port mapping is a software configuration so that it goes to the correct GEA cablelink service from the OLT using VLANs.
The FTTC OLT/L2S is quite often at a different exchange to the more local exchange MDF.
I'm not quite certain what happens with FTTC but certainly with normal DSL, BT uses something called SSB to ensure that the dsl side of things connect to the right ISP. During a migration period it is not unusual to be able to connect to both the gaining and loosing SP for a short period of time (couple of days) as long as DSL traffic is going out over the same VP.
I would need to look more into this area to be certain, but I know Openreach do use both C-VLANs (Customer-VLAN) and S-VLANs (Service-VLAN) to control (vdsl) routing from the OLT/L2S and on to the correct SP backhaul. I'm not sure how Openreach assign their VLANs other than they use VLAN tagging. It is possible when using VLAN tags to assign multiple tags, so in theory I suppose it
could be possible to do the equivalent of SSB using C-VLANs and S-VLANs.
On reflection they must do something similar to the above to ensure SIM provides & migrations go through smoothly. The frames engineer once he's done his rewiring on the MDF doesn't phone up or press a button to change routing at the L2S. Its the other way round in that once the VLAN side has been set up, then the frames engineer gets instructions to do the re-jumpering on the MDF.
Same new new FTTC provision the VLAN is set up and already in place before the fttc engineer is told that they can go attach the new tie pair at the cab. Any [old adsl] jumpers on the MDF can be left in place because once the engineer rewires to the cab, then its down the the SVLAN and CVLAN tags how your traffic is routed via the L2S at the headend exchange.
It is very rare I see 'Shared' (SMPF) circuits these days.
SMPF is incompatible with FTTC. Equivalent product would be GEA FTTC & WLR so as far as the Frames guys are concerned its same jumpering on the MDF as bog standard WLR.
The VDSL feed comes straight from the OLT/L2S No need for MSAN or HDF.
I'm sure I have a doc somewhere which shows the different wiring configurations on the MDF for various set ups. I'll see if I can dig it out later if anyone is interested.
I suspect that in this case something went wrong with the SIM migration. What that could be I've no idea and I will bow to your much greater knowledge of working in the field. I'm totally guessing but I wonder if the SP mucked up the migration by not passing it through correctly as a SIM order. If the SP only did the line order and passed dsl separate, then it could be a reason why the MDF jumpering was done and then the dsl bit was picked up as new needing a move at the cab to get the correct VLAN? God knows it doesnt quite make sense. Vodafone wont switch off their dsl side until theyve been informed by OR of sucessful migration.