New front garden

Hi everyone, this front garden has been under layers of thick concrete and soil leading up to the front door for at least 30 years.
We have totally excavated it (thankless task) uncovered steps we didn't know were there and re-routed the gas and water pipes which were left hanging in mid air.
The builders are coming to do a new hardstanding for our motorbikes, new steps to the front door and repaint the front facade of the house so it should look really nice.
The planting area will be surrounded by railway sleepers.
We've decided to leave a 12 foot by 8 foot approx piece of front garden (as shown) which we want to plant up in cottage garden style, herbs, a few veg, roses and flowers etc.
My question is, will this soil be ok after 30 years underground, should I add something to it or get some topsoil in? It's heavy clay, I could rotovate it being careful to avoid the underground pipes.

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I should add it's in full sun for most of the day and there are also large lumps of chalk in with the clay. We live on the South Downs which is a mix of clay near the river where we are and chalk from the hills. My garden is that yellow, thick clay which smells almost salty but plants, especially roses seem to like it.
i also want to grow a hedge up against and along the wall for winter colour. So far I have thought of pyracantha for security, cotoneaster horizontalis, euonymous. Any hedge has to be "clippable" as the gas meter needs to be accessible at all times for meter readings. So nothing too bushy. I'd appreciate any ideas.
I would have a narrow path in front of your windows for easy access to the gas meter. You could always have a couple of plants in pots at the start and finish of it too. Whereabouts are your pipes and how far down? It might be best to have plants that are shallow rooted where they are.
Pyracantha can be vicious. The thorns can be 2-3 inches long. You could have a lavender one. Not so much pruning and you can make use of the flowers when they have gone over.
If your garden is going to be surrounded by sleepers, you've created a raised bed, and I remember reading that you wouldn't need to dig over the soil, just top it up with topsoil and the plants roots will find their way down.
The soil will be very compacted, and though the mineral nutrients may still be there, the soil bacteria and other micro-organisms are probably depleted. It would do no harm to loosen it a bit, with a fork rather than a rotovator as you don't know what else might be down there, pipes , cables, etc. This would give the worms a better chance when you build your raised bed and add your topsoil. It would also help the roses and other shrubs, which will need a deeper rootrun than herbaceous perennials.
The gas man will curse you if you plant pyracantha
Cotoneaster makes a large shrub and can take up a fair amount of space. It is also not easy to prune it in a way that retains its elegance. Euonymus would be my choice of the three, attractive, biddable and easily pruned
Thanks to both of you, yes i love euonymous, especially the emerald and gold so I think I'll have that and just prune a window.
I did think Lavendar Garden Maiden but that part of the bed is shady thanks to the wall and I don't think it would thrive.
It will be quite a raised bed when he has finished with the sleepers and I think it would be ok to rotovate as my husband buried the pipes down about 4 foot himself so he knows where they all are.
I will order topsoil though. The earth is not in very good condition.
It looks horrible now but when the builders are done at the end of march it will look great
At last.