Firstly please don't take too much of the 'advice' you've been given on what you can and cannot do (your quote above 'l plan was to combination feed but was told by midwives I wouldn't be able to. I then asked if i could express instead so DH can help feed and i can pre-prepare bottles before going out etc... but I was told I wouldn't be able to do that until baby is at least 8 weeks old also').
I had low PappA, baby was fine and contractions started 36 hours after my due date, so wanted to reassure you on that, also read many stories about low PappA on here and all were ok.
Back to feeding, my DD is now 3 months and we combination feed, we started this about a week after she was born as her severe tongue tie was making BFing AGONY. At first it was one bottle a day for a while just to give me a break, at 7 weeks her tongue tie was fixed (far too late but NHS referral took ages for her some some reason) but I still combination feed, it has saved my sanity! I did it at first to relieve my nipples, I continued to do it as BFing in public is bloody hard with H cup boobs, it means my DH can take over overnight so I can catch up on sleep and also means I get to go out without her and she is looked after by my DH or one of her lovely Grandmas (trust me this is very important as a new mum if you're like me!).
I'm not sure why the midwives are saying what they have to you as ultimately you do with what works for you and you will only know what that is when your baby is here. I planned on exclusively breastfeeding and really hated the idea of formula (to which I feel incredibly bad about now) but now I love doing both, I even enjoy making up the bottles and prepping the formula.
I'm also glad we introduced the bottle so early as she was used to it from so young and goes between the two effortlessly.
I'm glad you have read up on colostrum too, DD wouldn't latch for days so had to hand express it into syringes, it was soul destroying for me as I don't think I'd really researched it, plus I'd had an awful 48 hour labour ending in an emergency c section and the BF consultants in the hospital were bloody awful. Midwives were amazing though.
As others have said above, as you are open to both, try BFing and go from there. There are pros and cons to both so in a way combination feeding for me is a win win!