Thing is, your major cost in the slabs so if it really isn't going well then you put your slabs to one side, abandon ship and get a pro in. You'll still have saved money if you've dug out and laid the sub base yourself....
To add - I found it a massive amount of time and effort to get the base...
I did say comparatively speaking! TBH, when I left Shoreham 3 years ago, putting a shelf up was a challenge, if I can do this stuff, anyone can, trust me...
As mentioned elsewhere, I'm building a patio right now, it's 49m sq and has cost about £2.1k in materials, quote from a builder to do it was £4.7k. It's taken me about 2 weeks thus far and while I am a complete amateur, it is time consuming, you've got to dig down to the earth's crust for...