Time to redesign the veggie plot (with pics)

I have a south facing veggie plot at the end of my garden which predominantly consists of four raised beds.

I have done quite well with them over the last three years, but I have a few issues with them:

1) They are not big enough! They each measure approx 1.5m square. Whilst I have done quite well squeezing maximum croppage out of them, I would still like more space.
2) They are quite high raised beds - about 60cm. I have little choice on the raised bed side - the tree roots stop me digging up the area and planting direct, but they are prone to drying out really easily - even with all the manure and compost I can get my hands on. Dripper hoses have been a good answer on drier days.
3) I have little room for permanent planting - such as fruits and herbs.
4) I had an arch stretching across two of the beds which I used to grow a butternut squash and runner beans on which was broken by recent high winds
5) I have a birch tree which is now growing over one of the beds.

Pictures of the area are here, here and here. These photos were taken in their first year before the paths were completed but the veg was growing well, they still pretty look much the same now (although a bit more dead!).

So, I have decided to change the area as follows and thought I would share with you my plans:

1) Merge the two beds on each side into one large longer bed either side of path. My OH was quite upset initially with this, because he worked so hard on building the path around them - but I need more growing space!
2) Lower the bed height, reusing the wood to join the beds.
3) Use up the compost from my over-brimming composters, growbags and the pot grown potatoes to boost the levels of the beds.
4) Put up three wooden arches which I bought on ebay to replace the one broken one for growing beans and other stuff such as squashes over.
5) Join the arches with twine and grow raspberry canes or other fruits to line the path in between.

I have planted my winter veg in modules under cloches, intending to redesign this area asap, so I should have plants to put in there once done. I also have some onion setts and garlic to plant.

I have other needs too. I would like to plant a rhubarb plant that currently lives in a pot into the area occupied by my redundant green cone (rat nightmare so now abandoned). I would also like to create more room to grow potatoes in pots next year.

I am sure there will be other things too.

Thought you guys might be interested in the project anyway (my family are bored with me talking about it!!!)

I would appreciate ideas on fruit recommendations to grow along the twine between the arches. I already grow hops and grapes successfully over a pergola elsewhere in the garden and have a (so far sterile) cherry tree and a poorly performing apple elsewhere too. I moved the strawberries out of the beds when room became a problem and have since grown them in a trough with little success.

I am down on the South Coast - we have very mild winters and because my garden is walled and landscaped (no time to cut grass) it can get very hot and dry in summer. I work fulltime, so only get time on the weekend to work on my plot and I am organic where possible (hence the netting over the plants to prevent cabbage white invasions! I do occasionally resort to a small quantity of slug pellets when I become over-run.

Any tips/encouragement greatly appreciated!!!! Thanks!