How about making a living willow arbour from willow canes popped in the ground they should regenerate their own roots and form to make a teepee which can be sat under or a chamomile bench is easily achieveable! Native hedging is very valuble to birds hedgehogs and all manner of insects and trees can cost as little as £2 a tree!! Pond creation for Newts, frogs and a whole lot more and then theres lots of wild flowers which are beneficial to all manner of insects. The more diverse the better