Care agency or carers for serve disability

HI
We have a family member with serve disability (Brittle Bones). He is currently been cared at home.  We currently have two carers been provided by care agency from the council, however over the past couple of months they have become so unrealiable that one carer turns up and they do not have another carer to help. Issues also arise when main carer may go on holiday. 

We are now exploring option of finding a new care agency or carer direct. Can anyone recommend a good care agency that specialise in providing carers in home for someone with serve disability. Location  HA3 (Harrow)

The individual would need to:
Morning -  bath, dress, feed, provide medication & sit up in the wheelchair in morning for 2 hours  evening - 1 hour call  would be requiered to transfer from wheelchair and lie down, change into night clothes and personal hygenie.

If you have employed carer direct through direct payment what has been your benefit and any lessons learnt we need to consider.

If you have experienced any challenges with Social Services on care provided, what approach have you taken.

Thank you in advance