Who are the finest UK design and dev companies...

It looks like we've got a big customer to buy in to our iPad (and other touchscreen device) based system for them. It will be an on device app but will reguarly look to a central system for updates of data. I don't think you'll need specifics as my question is simply this:

The budget is solid - who would you recommend we speak to for the best quality design, service and underlying development? It needs to be beautiful, functional and easy to maintain and update.

There will likely be a regular flow of work after this initial contract so someone with a UK presence, even if they manage development off shore, is key.

It'll be a series of large projects and lumpy so don't think a one man band could offer the service we need