It's a 5 year visa journey to the UK for her, if you get married and want her permanently residing with British Residence Card (BRC) and meet the financials.
Otherwise a 6 month visit visa every year, if the visa rules are not broken and financials are met.
I brought my then Thai GF over for the summer months, then visited her during our winter months.
We got married here and went down the 5 year residency route so she could work, pay taxes etc. But we are now both heading to Thailand as UK has lost its way a bit and forecasts are not favourable unless you love paying taxes!
The IO comments are final..has he/she written anything on your passport stamp? But it is a bit harsh..I came in 1st January on 60 days then left 31st January and came back 3rd March no problem.