Schedule of movement of provision for allowance for credit loss of retention receivables (Details) - HKD ($) |
12 Months Ended | |
|---|---|---|
Sep. 30, 2025 |
Sep. 30, 2024 |
|
| Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] | ||
| Provision for allowance of credit loss, beginning balance | $ 510,000 | $ 307,040 |
| Retrospective adjustment upon adoption of ASC 326 | 302,960 | |
| Reversal of provision for the year | (90,000) | (100,000) |
| Provision for allowance of credit loss, ending balance | $ 420,000 | $ 510,000 |