At the end of the day they have the full right under the law to pull a hard pull. You are seeking more credit. Its a dick move but some like CITI enjoy clicking the button.
I personally do not have any business with HSBC but I can report they are one of the better ones out there.
Financial Institutions like to work with one credit reporting agency typically. Most use EQUIFAX on the FICO Score 8 model. If you have a AMEX card they provide you a free FICO SCORE 8, and this is better than Credit Karma as they use the vantage model.
If they are frozen then I wouldnt worry about nothing anymore. If its a hard pull they would request you to remove the "lock" on you're report. Most lenders do not even use T/U. I have one credit card that has never reported to them.
I asked for a CLI from HSBC once last year and it was a HP (Equifax).
Even though I am a Financial Analyst, and have helped hundreds with fixing their credit, and winning the system, I must say this needs to be an indvidual decision.
1. Can you afford the hard pull?
2.Do you need the increase for something beneficial like a new car?
Expect a HP and you need to give it 6 months in between requests for a CLI with HSBC.
This ^^^^ OP, plus the comment from @ttulaw. In rare instances are CLI requests SP (except auto-CLIs). Of noteworthy, if your reports are frozen, you'll need to thaw them or the request will likely be declined.
It can be hard or soft. I requested a CLI around April 2018 hard pull, took a stupid hit. Requested another one November 2018 this time made sure my equifax was frozen, they denied and told me to call. Said to thaw if they want me to review. Forget that! So the other day on the July 9th 2019. I froze all my reports again, and hit the CLI button. Surprise! Approved for additional 50% of current limit!