2000 Renault Clio not starting

Hi Dave, thanks fro prompt reply. I have been away, but now working on car, and am grateful for any advice.
Have pulled timing belt cover off, found belt to be still intact but frayed. ( Had garage replaced the timing belt abt 1 year ago at 55,000 miles) Inlet valve timing gear has a plate at front (all part of gear), this has sheared and about 3 inches missing. Found strips of this plate all squashed up within cover.
Undone tensioner, at the back of the tensioner, there is a locking tag, the tag facing towards the tensioner seems to be twisted a little.
Removed the belt, and found the inlet valve camshaft turning freely. No valve spring tension.
Removed the top cover to expose the camshafts.
Found all rockers under the inlet vavle camshaft were all out of thier positons, (had dropped out of their seatings)
Not sure as to how this has happened, wheather this happened at the time the engine broke down or later when attempting to start it.
In your opinion, is it wise to remove the cylinder head for examination or to refit the rockers and new timing belt and tensioner.
Look forward to your reply, thanks again.

Hi Dave, Thanks for your reply. I have already removed the head and as you correctly said. All valves are in fact bent. The piston heads have been gouged. But i'm thinking of not disturbing the pistons. I may try and replace all valves or try and obtain another second hand cylinder head, which will come with camshaft gear attached. As I said on my first post that the flanged plate on inlet camshaft gear has sheared and part is missing.
Would be grateful, if u can adivise on setting up of timing, particularly as to, how to know when piston on TDC is on compression stroke and not on exhaust stroke? As I guess spark and fuel injected only on compression stroke? Thanks for help.

Hi Dave, thanks again for reply.
Have not had time to dismantle head yet, too cold in uk haha, will revert to u when I have dismantled.
Have got the workshop manuel.
As far as getting camshafts in positions, there r slots in tail end of shafts. These slots are off centred, one has to attach a tool or plate in there and screw to head to lock up. No marks needed on cam gear.
Then to get piston on TDC, ( there is a tool thats is slide in side of engine block which locks against crankshaft web, basically it is a pin) slide belt sprocket on crankshaft ( there is no key in sprocket), slide on pully and tigthen to specific torque.
My question is, how do I know I have got the piston on TDC on correct stroke, that is on compression stroke. It cud be that its on exhaust stroke?
If on exhaust stroke then fuel be entering incorrect cylinder and sparking on incorrect as well (360 degrees out on crankshaft) Let me know what u think. Thanks.

Hi Dave,
Thats excellent, will give it a go.
Just lilttle unclear as to know, once we set valve timing to No1 cylinder on TDC on comppression stroke, there is no disributor to check the rotor is pointing to HT lead to No 1 cyinder (like in older engines)
Was just wondering if ignition timing can end up being 360 degrees of crankshaft turn out? Meaning if firing order is 1342. And instead of firing on 1. Cud end up firing on 4. Which wud be on exhaust stroke.
Hhmm okay Dave. Revert to u. Shortly hopefully wid engine running sweetly.

Hiii, thanks for your help, understood now, will revert to you once I have progressed matter.