I think there are no limits for accounts that are in the same name (the one with money being tranferred to and the one with money being transferred from) but there may be from one person to another. As it is the same bank/building society there likely won't be a fee though. Best bet is to check first as access wrote.

There are stops and measures in place to prevent abuse though, specifically to stop money laundering, tax evasion etc so they may ask your purpose and or permission from the beneficiary in advance with some of the anti-terrorism regulations in place. (Not sure if it does/will apply to you (depends on the circumstances and specifics involved) but it could).

A check usually clears same if its over 10K these days but 6K would likely take you the 3-7 (variable) working days.

There are limits in online banking BUT with both Barclays and A-L you phone and they do it up to an agreed per day limit. Halifax to Halifax I would have thought is no problem but give them a ring and if you don't know about and it works for you get a geographic from saynoto0870.com. Or this may well do you - 01422 333232.

Is there a limit on how much you can transfer from one Halifax (my uncles) to another Halifax (mine) account?

The amount to be transfer is £6,000. The other way is to write a cheque and get a Special presentation which costs around £15.00p but that’s not guarantied it wont be in the bank next working day.