I've been trying to ARIMA models for the UK nominal GDP. I've determined the I to be not stationary - I(1). And now am having trouble identifying what the AR(p) and MA(q) would be from the linked correlograms:
ACF for differenced variable (https://imgur.com/qZp6nWF)
PACF for differenced variable (https://imgur.com/IybguSy)
My initial thoughts were: since there no pattern for PACF, MA is 0. And because of the 2 significant spikes in PACF, the AR would be 2. But I'm confused about relevant lags.