Really? I know it's going back some but when we had ds1, people from an organisation called ShareCare or maybe it was CareShare used to come & look after him once a month or so, at a very reasonable charge.
It would be worth looking into voluntary organisations, like maybe Scope, Barnardos etc. (though maybe you already have).
Make sure the social worker knows about it [the agency won't tell him/her that's for sure] and then get him/her to have a sharp word with the agency. (Also worth contacting the contracts/commissioning team at your local authority.)
If the agency gets lots of complaints/late calls, that'll go against them when it comes to contract renewal time.
Some of these agencies are utterley shambolic and couldn't be trusted to run the proverbial piss up in a brewery....
Riven I work as a respite carer for Crossroads. I don't know if you have them in your area but they might be worth looking into as extra help. I am sure they would be able to help you. www.crossroads.org.uk
Please check that because I have looked after lots of chidlren in my time including during the summer hols/weekends/evenings. Maybe it's a different scheme to ours. We cater for all!! Direct payements is a good idea.
Sorry to hear that. Also sorry to hear about the agency-does this happen a lot, might be time for a quiet word. I know how precious the time is for carers. Sadly I hear lots of stories like this. Transport is another big problem. Sorry to hear your Crossroads scheme could'nt help. Good luck & God bless.