Thanks for that.
If the door handle is jammed solid then unplug the appliance.
Wait 5 minutes.
With the appliance still unplugged, try to open the door.
(Push on the door to close it and help relieve the tension on the lock when you are trying to open it)
If still locked, give the front panel next to the handle a couple of good thumps to try and jar the lock loose.
If still locked, try pushing the door closed while pulling down on the tab.
If still locked, take the top of the machine off.
Reach inside to the door lock and try to release it there.
If it still won't release, work the lock back and forth, side to side until it comes off of it's screws.
Lift the lock off of the latch and open the door.
In this instance, you'll need to fit a new door lock.
If all else fails, protect the paintwork and lever the door open, breaking the door latch and lock.
In this instance you'll need to replace the door handle/latch assembly and the door lock.
You may already have tried some of these methods but it's worthwhile going through them again.
The only alternative to doing this is to call someone in to repair the appliance.
Click here to find a repairer in your locality
Just fill in your details on both pages and the company you choose should contact you.
Alternatively, Hotpoint will come out and fix it for a fixed price. Give them a call and see what they are charging and what plans are available.
Their charge will include all parts and labour.
Hope this is of some help
Let me know how it goes or if you need more help