Fighting to keep grandchildren

[flinds]

Just over a year Social Services placed our grandchildren with us,a girl then aged 2years and a baby boy, 2 months. We have loved and raised them successfully since then and accepted that our daughter (who has slight learning difficulties and psychological problems) will never be allowed to have them back. What we can't accept is that SS want to have them adopted even though they are happy and settled with us and we desperately want to keep them.
The chief problem seems to be the potential bad influence of our daughter. She has recently been evicted from her local flat, left the area for 2 weeks, came back, homeless. Within 24 hours SS were on our backs because she was 'living'with us (she is normally allowed to stay 2 nights per week and we had given her a time limit of 4 days to find somewhere else).
This is just a snapshot of what we feel is unfair treatment by SS (we have made an official complaint about their assessment of us which is full of inaccuracies and lies). We have been co-operative and transparently honest throughout (as teachers we thought we were dealing with fellow professionals) Any advice out there?

Lindsay