Scummymummy - first off, rack your brains - get our your address book - have you or your dh any friends or relatives who you could visit - and, most importantly who you would want to visit? Even better - do any of them have holiday homes, caravans etc?
Do you have any friends or relatives who might want to swap homes with you? Perhaps the area where you live would be a highly attractive destination to a county cousin or a friend from abroad? I used to live in a flat in Peckham. The American friends who visited me thought the pie and mash shops were enchanting and were happy to hop on the 53 bus for trips all over London. I then visited them in the lush suburbs of New Jersey.
Ask favours, make enquiries, nothing ventured, nothing gained. And, if you want to make your visit to the chosen friend/relative shorter than a week, you could combine it with youth hostelling. Or just go on a youth hostelling holiday.
The YHA website shows you pictures of all the youth hostels and gives you heaps of info. Don't know much about YHAs abroad, but this could be worth investigating.
Many British YHAs are designed to be family friendly. Some have camp sites attached. There's a lovely stately-looking YHA in Salcombe, South Devon for instance. The area has great beaches as well as lots of toddler-friendly attractions. Prices are about aprox £11.00 - £16.00 per adult per night - toddlers might go free, or, if not, the cost is much less. And it's self catering, so you don't have to spend loads of cash on eating out.
Anyway, if I think of more suggestions, I'll post again.