43 Inches, whilst I agree with the sentiments re SARWATCH, being told “Air Traffic Services Terminated, TIBA procedures apply, Frequency change approved” would implicitly suggest to me you are now getting no service; there surely is no doubt.
From AIP Gen 3.3
A position report must be made on the next CTA/FIA frequency 15 minutes prior to leaving airspace in which TIBA procedures apply to obtain a clearance or re-establish SARWATCH on the appropriate ATS frequency.