After much messing about with hoses and water, I couldn't get a reliable water circulation. There was a 'high' point in one of the hoses to the pump (intake) which would air lock and then stop the flow. Knowing the seals in the pump were iffy to say the least I decided to pull it to bits. Oh dear, not a pretty sight! Faced with the option of buying a reconditioned pump at well over £100 I decided to see if there was an alternative. An electric one was a possibility, but again, about £150.00. Trawling the Internet for Hillman Imp parts I came across http://www.corley-conversions.co.uk/  A phone call on Saturday morning resulted in the answers I wanted to hear, 'Yes we have a rebuild kit and you are welcome to collect it anytime today'. Armed with the bits of my pump I took a drive and met Ben Boult who gave them the once over and all the tips on rebuilding it. Thanks Ben!
By late Saturday afternoon the pump was refitted in a different position to avoid air locks. Now circulating fine, and seems to keep it's cool, although I think there is a need for a larger capacity header tank which I will plumb into the top hose.

I reconnected the Alternator (which didn't seem to work when I tried it a couple of months back) and after a few seconds of the warning lamp flickering it went off and gave an output. Perhaps worth the tenner after all!
Thought I would include a video of the engine running. A shame the camera started to slip...........

Engine runs

No picture I’m afraid, but an update on engine progress. First runs a few weeks back proved the Aquaplane head did a good job of filling the bores up with water, so that has been set aside for a skim and re-fit at a later date. As it also seemed to be running hot, I thought it better to get it running right with the cast head. With no expansion tank in the cooling system, it was also too keen on blowing water out of the vent. For some reason it seemed to be running lean, so the jets were adjusted down, but no great improvement

An electric cooling fan and a Landover expansion tank grafted on, it was time to have another play with the carbs. Everything was checked, jets centred, the air slide dropping correctly but it was still not running too well. It seemed to have a nice high speed tick-over with the choke on even though the butterflies were fully closed. Just pondering where it could be drawing its breath from I put a spanner on the manifold to block bolts..............and yes, fancy not checking them when I fitted the carbs! Now running much better.  Will have a go at setting up the mixture with a colour-tune widget at the weekend. I don’t think the neighbours are so keen on hearing the exhaust note late evening as I am!