filling in the prayer part of D8 form

Taking the plunge and filing the form on a self rep basis this week. One last remaining question though which I would appreciate some help with. Don't want to get it wrong and delay the process though.

I have left FMH and kids reside with their mother. I know I will have to pay STBX maintenance as well as child support. As there is no way I will be getting maintenance/child payments from her, should I cross out the section for Ancillary Relief in the prayer?

Hi fieldy. Sorry you find yourself here but you will get all the support you need.
The application for ancillary relief is to sort out the finances at some point.
Don't cross it out - Keep all options open - You might use it & you might not for assets, house sale, and pension sharing.
But if you cross it out at the start you forfeit the right to use it later.

if I leave it open do I also have to file form A at the same time as the D8 and statement of arrangements?

Not necessarily at the same time. You are just keeping your options open at this stage.
The court costs for each form presented is still payable per form, Whether they are sent together or separately.

You will need to get CETV valuations for any pensions & a recent house valuation to send with form A. Take your time & get it right.

Look at the advice forums & go into chat for lots more experienced advice. Good luck.