Estimate for UK Jan 2019:

SMMT Other Imports for Jan is 207 units. Last year in Jan, non-Tesla portion of Other Imports was 64 units. Assuming the non-Tesla portion stays the same, the Tesla portion this Jan would be 207-64=143 units. Out of those 143, I estimate 81 are Model S and 62 Model X.

Estimate for UK Feb 2019:

SMMT Other Imports for Feb is 139 units. Last year in Feb, non-Tesla portion of Other Imports was 60 units. Assuming the non-Tesla portion stays the same, the Tesla portion this Feb would be 139-60=79 units. Out of those 79, I estimate 45 are Model S and 34 Model X.