OCD checking help and advice welcome

Hi.
I am struggling with checking and wonder if anybody as any help/ advice for me.
The checking is worse just before bed and can take me between 15mins to 1 and half hours to complete my checks. It’s worse when somethings on my mind or my wife is working nights.
The checks include doors, lights, sockets, fire and morning alarm. I know I have done them all but there’s always doubt in my mind that makes me check again in order.
The checks started around 13 years ago when my daughter was born.
I saw a therapist 5 years ago for a dozen sessions that helped a little but the checks have got worse.
Any advice and help would be appreciated
Thanks
Mick