Your ISA with us is a ‘Flexible ISA'. This means any money you withdraw during the tax year, you can replace in your ISA in the same tax year without impacting your ISA allowance.
For example, if you contribute the full £20,000 into your CIRCA5000 ISA within one tax year and withdraw £2,000, you can put the £2,000 back into your ISA before the tax year end without going over your annual allowance.
Please note that this may not be the case with any other open ISAs you have. Not all ISAs are Flexible ISAs.