im looking to apply for a mortgage with my partner (she is an existing home owner and I will be a first time buyer).

her credit record is absolutely clean (£3000 credit card limit which, if used, is cleared in full upon receipt of the monthly statement and also 2 years plus of her own mortgage payments without issue).

unfortunately my credit record is no where near this perfect. I took on most of the credit risk in my name with a previous partner and then when things went wrong I was left with the debt which became unmanageable and subsequently meant I defaulted on all of the agreements (something for which i take full ownership and responsibility).
My worst credit record shows 21 adverse accounts which are as follows:

NOTE - the amounts shown are remaining balances - I am continuing to pay £200 pm in total to clear everything but there is approximately £9000 o/s.

OVER 24 MONTHS
Moorcroft (Comms) - 30/08/2019 - £675
Moorcroft (Comms) - 30/07/2019 - £341

OVER 36 MONTHS
Onstride - 01/02/2019 - Satisfied
Lowell (Comms) - 01/01/2019 - Satisfied
BT - 28/11/2018 - £171

OVER 48 MONTHS
Halifax CC - 24/05/2017 - Satisfied
Halifax Acc - 23/02/2017 - £1131
Lowell (Comms) - 02/02/2017 - Satisfied
BT - 26/10/2017 - Satisfied

OVER 60 MONTHS
Intrum - 07/10/2016 - £87
Hoist - 31/01/2017 - £581
Orange/EE - 22/10/2016 - Satisfied
Lowell (Comms) - 14/08/2016 - Satisfied
Lowell (Credit Card) - 03/10/2016 - Satisfied
Paypal - 05/09/2016 - £1116
PRA Group - 31/01/2017 - £1601
Link Financial - 03/09/2016 - £3450
Wonga - 28/10/2016 - Satisfied
Lending Stream - 21/01/2017 - Satisfied
Barclaycard - 03/09/2016 - Satisfied
Barclays Partner Finance Loan - 31/01/2017 - Satisfied
Halifax Current Account - 07/10/2016 - Satisfied
MBNA - 01/01/2017 - Satisfied

we are looking at a property worth £350,000 with a total deposit of roughly £70k.
we earn a combined salary of £76,000 (not including my bonus or my partners second job).

This deposit is from the sale of my partner (the joint applicant) house. She has offered to pay the debts for me but i'm determined to pay my own way and i'm also conscious that we are likely to need most of this deposit if we are to be successful in finding a mortgage.

As if I couldn’t complicate things further I am due to start a new job in April for a significant pay increase. I’m less concerned about the new salary being used for affordability - my main concern is whether or not I will be acceptable when factoring in everything else.

We'd like to be applying for an agreement in principle within the next couple of months but the full application wouldn’t be until the end of the year when the house we’d like is built.

I don’t think I’m missing any details but could anyone give me a steer as to whether or not I stand a chance at being accepted on a joint application for a mortgage?

thanks in advance.