Micra K12 Intermittant Issue : P1122, P1126 & P1128 Codes

Hi Guys

I'm after some advice ....
My daughter has just bough her 1st car, a very clean Micra K12 1,2 S Manual with 66k miles, 2 owners and full service history.

Shortly after buying (Private sale) the engine check light came on but the car ran fine. However, the following day when driving the car went in to limp mode and would not do more than 2.5k RPM so rather embarrassing to drive at <10mph. Turning the engine off/on seemed to fix the issue at the time but the issue got worse to the point where it was stuck in limp mode.

I bough a cheap OBD2 diagnostic box and determined that all three codes related to the electric throttle assembly;

P1122 - Electric Throttle Control Performance Problem
P1126 - Throttle Control Motor Relay Circuit Open
P1128 - Throttle Control Motor Short Circuit

and after reading these are weak on the K12 I ordered a 2nd hand one, ensured it was clean and replaced the original. I went through all the re-learning procedures yesterday and the car seemed to be fixed as I drove 8 miles of mixed driving with no issues.

However, today I took the car out for a final test and after about 1 mile the engine check light lit up again and the car dropped in in to limp mode again. Same check codes of P1122, 1126 & 1128 are back again.
When starting the engine now the RPM sits at 2krpm - I did the re-learn again which seemed to fix the high idle but after about 5 mins the rev's went back up to 2,500 rpm.

I've checked all connectors, plugs and ground point and all look OK.

Due to the intermittent nature of the issue I'm suspecting either a dodgy wire or the Throttle Motor Relay, however, I understand that there is not a separate relay and that this is built in to the circuit of the IPDM (Power Distribution Module) that's under the [passenger head-light in the engine bay.

I've ordered a 2nd user IPDM from a Micra of the same year & engine but does anyone know whether I can simply swap the entire box or if it needs to be programmed to the car by a dealer? ...... it's not the ECM I want to swap, but just the IPDM with a part code that Nissan has confirmed is correct for my car.

If the IPDM does need to be programmed and I do swap it am I likely to cause any damage?
at the very least it may help confirm if the fault lies with this box or elsewhere.

Any advice greatly appreciated :)