Thank you Fred,
One difficulty is I can't seem to make Root or Home logical partitions as the choice is greyed out. The partition are still pending I haven't set them yet but I have followed more or less your scheme with 250 MB Fat 32 EFI, 1 MB unformatted,48.83 GB Root EXT4 (I install a lot of programs), 39 GB Home EXT4 and 23.65 unallocated. Presently all partitions pending are marked Primary-do I change that after I apply the settings? And do I then create a partition table in GPT for all partitions?
Oh and I have 16 GB of RAM so I have not created a SWAP partition but it is not too late
edit-Is it necessary to set any flags?