Leak detection is usually carried out on a single visit.
There are times when further visits are required, which are chargeable at the same rate; however this is rare, and there is usually an underlying reason. Lack of access (particularly in flats) and blockages in heating systems are the typical issues. When undertaking insured works, there is normally an amount set for this of £5,000 by the insurer, and they will cover unavoidable re-visits.
Once the leak is located, we offer intrusive access to the leak at the same cost as leak detection. Again, this is covered if you have trace and access on your building insurance, and when deferred payments are used, it should not be an issue.
Once accessed, we recommend an independent plumber repair the leak to avoid issues with insurance and cover costs (such as the repair) classed as maintenance.