Testing my lenses in Cornwall - advice please!

[Raider]

Well equiped with my recently purchased 70-200mm F4 + 1.4x TC I went to Cornwall this weekend along with my also-new Sigma 10-20mm. So my kit bag contained:

Sigma 10-20mm
Canon 50mm F1.8
Canon 18-55mm kit lens
Canon 70-200mm F4 (98-280mm F5.6 with TC)

Starting with the new lens, as superb as it is, I was still craving the extra length, even at 280mm. Whilst my original plan was to buy a 300mm F4 separately, the extra weight and bag requirement would be difficult.
Hence I'm thinking now of swapping the 70-200mm F4 / 1.4TC for the 100-400mm L IS.

I've also found myself not really using the Sigma 10-20mm. I'm thinking instead a more conventional zoom might be in order, namely the old 17-40mm F4 L.

So what would people think of selling the 70-200mm F4 / TC / 10-20mm and replacing with 17-40mm F4 & 100-400mm L IS?

 

[Raider]

Well just been offered a 17-40 L for £425 off Kerso, so £355 inc Cashback. Think i'll be selling my 10-20mm pretty promptly now!

 

[Raider]

Well I think my mind's made up. I'll be selling the 70-200 and the 1.4x TC and replacing it with a 100-400L

Then in a few months, if money allows I shall probably get a 200 F2.8 L, that way I can have a nice sharp and fast lens in the mid-telephoto range. Does that seem like a good idea?

 

[Raider]

For the occasion when i'm on the coast it is useful yeah, but I guess I don't take that many landscape shots. The ones that I can take at 17mm are just as good. No funky effects for sure, but still good