Well, all depends on what you call reasonable.
I don't know which engine you have, so these links are based on a 1.2
Considering that for a competent home mechanic can easily swap out front brake discs and pads, new discs and pads can be had for this price:
http://www.ebay.co.uk/itm/FIAT-500-...hash=item2ec4309644:m:mYo_K6RBVcDzUKDxHRs6dcg
Wishbone, well, how much do you want to pay and which brand? If you're not fussy, a new offside wishbone will cost this much:
http://www.ebay.co.uk/itm/FIAT-500-...795944?hash=item51dd65eea8:g:01AAAOSw5IJWcrUQ
So, just on those items alone, they'll come to just over £60. I'd find a good independent garage and get a quote for fitting only if you can't do the job yourself.
Concerning rear shocks, again, you can go cheap or expensive. Personally, I'd replace with Bilstein standard replacement shocks, but if money is an issue, you can opt for these:
http://www.ebay.co.uk/itm/2-x-Rear-...648161?hash=item2ca2b9d2e1:g:hSgAAOSwN81WEk4K
Basically, if I were doing the job myself, the MoT pick up points would cost me less than £100 and doing a basic service would add another £40 on top for oil/filter, plugs and air filter.
The links I inserted are for guidance only, please don't take these parts as the actual parts required for your vehicle. It is your responsibility to check if you choose to purchase.
From my perspective, the quote is way above what I would pay, but if you haven't spent a great deal on the car since you bought it and you intend keeping it, then you might just want to pay whatever the best quote you get for the work to be done. My advice anyway is, get three quotes if you can, never accept the first quote:
https://www.goodgaragescheme.com/
You could also consider a mobile mechanic. I've used a mobile mechanic in the past, and he was very good, with much lower labour rates than a garage would charge.
Here's the link concerning re-test fee/partial retest:
https://www.gov.uk/getting-an-mot/retests