British Expats - Moving back to England from Spain

I really dont know where to start , we have sold our business in Spain and are planning our return to England, there are lots of things that i have lost touch with , but have so many questions , sorry . We obviously intend on going over to buy a property thats the first move, so that we have an address, I have a son and have applied for schools which has gone quite smoothly but obviously they need an address in England which we will be able to give once purchased then he is entered , he was born in Ibiza but is a british citizen as we all are, so that it one tick. Now i have a poorly mum who is on oxygen 24 hrs and also has machines for her illness that she uses all day at certain times, therefore i need to get this sorted before we make the final move, as she will be unable to travel backwards and forwards as we intend doing , she really is only capable of doing one trip, would i be able to register with a doctor and get medical machines in the house without her being present ? Also can anyone answer as to whether when we make a cash purchase on a house (no bank involved ) will we be taxed as we are paying a massive tax here in spain on selling? Also on my husbands side at the age of 61, there is obviously a system in which he will be able to claim his pension from here ( 18 years worth of stamps paid ) and recieve it in England , does England then take that into account or is it a seperate entity? Really dont know where to start this end, as we know Spain loves paperwork, we obviously have to hand over all forms of residency here as we will go on electarol role in England . Really what we want to do is leave here with no bank account etc still open and start afresh in England ,Any help or if anyone has done the same and could advise me of procedures etc, i would be most grateful, have lost touch with the english system being here so long , many thanks for any help you can give me, Kind Regards