In my opinion I think that a mortgage is out of the question unless you want to pay extortionate rates and by extortionate I mean 10% -15% (compared to normal rates of 3% - 5%)
Yorkshire BS will not be able to help you here either. While they do take a little adverse credit they will not accept as much as you have along with it not being "satisfied" and also your "arrangement to pay".
The 3 main things that you have going against you at the moment are:
Several defaults - not so bad in itself as they are a few years old - will fall off your credit record altogether after 6 years.
The defaults are not satisfied - This is an absolute must if the default is anything over £250. If it is over £250 then the debt must be satisfied (repaid) at least 12 months for most companies before they will consider for a mortgage....some will accept a small amount unsatisfied.
Arrangement to pay - This reduces your credit score to practically nothing (if the defaults have not done that already) No lenders like debt management plans which is what an "arrangement to pay" is and as such most lenders would decline you on this alone regardless of the other factors.
I think your best bet is to rent a new property where ever that is for at least a year and if you can try and rent your existing mortgage property, this will at least cover your mortgage payment on the house and maybe even some on your new house